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EVGA Launches 4-Way SLI Motherboard

Paul Lilly — Thu, 03 Sep 2009 08:30:40 -0500

Running a pair of dual-GPU GTX 295 videocards gives gamers quad-SLI bragging rights, but if you're really serious about driving Crysis cranked up on your swank 30-inch display, EVGA's new 4-way motherboard might be just what you're looking for.

EVGA's X58 Classified 4-Way SLI board supports up to four videocards and coincides with the company's 4-way compatible GTX 285 Classified videocard. Currently the fastest single-GPU videocard on the planet, four GTX 285 cards should trump two GTX 295 cards in just about any situation.

All that design decadence comes at the cost of case real estate and you'll need a chassis that supports the XL-ATX form factor. Measuring 13.5 inches by 10.3 inches, EVGA warns you'll need a case with 9 or more expansion slots, or handy modding skills.

The 4-way board is available for pre-order now for $450 direct from EVGA.

Image Credit: EVGA

EVGA Launches X58 SLI Micro Motherboard

Paul Lilly — Thu, 02 Jul 2009 09:35:33 -0500

EVGA set out to prove it's not the size of the motherboard that matters, but how you use it. And with the release of the X58 SLI Micro, you can use any speed grade Core i7 processor you want along with a pair of Nvidia graphics cards all in a micro-ATX package.

In addition to 2-way SLI support, the new mobo also crams 6 DDR3 memory slots (supporting up to 12GB of triple channel DDR3-1600MHz+) and 6 SATA II 3GB/s ports onto the mATX board. Other features include 100-percent solid state capacitors, VDroop control, an onboard temperature monitor, support for up 12 USB ports, a single LAN port, a passive heatsink for cooling the chipset, RAID 0/1/0+1/5 and JBOD support, and 8-channel onboard audio, all decked out in a red and black color theme.

The board is available now for $200.

Image Credit: EVGA

Ultimate BIOS Guide: Every Setting Decrypted and Explained!

Paul Lilly — Mon, 15 Jun 2009 12:35:52 -0500

Power users routinely punch into the BIOS in order to fine tune their system, but it can be an intimidating place to go exploring if you've never before burrowed beneath the surface. And just like in real life, poking around in unknown places can be a dangerous affair if you don't know what you're doing or where you're going. On the other hand, once you understand the inner workings of your PC's control center, a whole world of overclocking and troubleshooting suddenly opens up. But what exactly is the BIOS?

Every modern motherboard comes with an embedded Flash EEPROM module, otherwise known as the BIOS chip. Short for Basic Input Out System, this is the first bit of code executed when you boot your PC. The BIOS stores all kinds of essential information about your system, such as your CPU's clockspeed, the size and type of RAM you're running, the boot order of your media, what onboard devices are present, and much, much more. An improperly configured BIOS can prevent Windows (or Linux) from loading, while a finely tuned BIOS has the potential to significantly improve performance over that of a similarly spec'd machine.

Whatever your goal is, this is your go-to guide for everything you've ever wanted to know about the BIOS. We cover every setting -- even the obscure ones -- so you'll never feel lost or out of your element, no matter what motherboard you're rocking under the hood.

Check out our Essential BIOS Tweaking Guide here

How do I Get In?

Whether from a cold boot or rebooting, getting into your BIOS is as easy as hitting the DEL key as soon as your system starts to POST. You might even see a Splash screen instructing you to hit DEL, but this isn't always the case. If mashing the DEL key doesn't do the trick (some OEM setups, notebooks, and older PCs use a different key), try punching F1, F10, or the ESC key. For really old PCs, you might even need to hit a combination of keystrokes, in which case your best bet is to consult your user manual or the modern day oracle known as Google for the correct sequence.

Main BIOS Menu

The overall layout will vary depending on your specific motherboard model and BIOS type, but every modern BIOS shares the same basic settings. We're going to cover those now while using a Gigabyte X58 as our test platform.

Standard CMOS Features

Exactly as the name implies, this is where the standard settings are located, including the date, time, and drive configuration.

Date and Time: You shouldn't need to configure the date and time more than once, but if it keeps getting knocked out of whack, it may be time to replace the CMOS battery. You can try leaving your PC on for an extended period of time to recharge the battery, but it's cheap enough to replace outright and a new one should last for years. Check your motherboard manual for the type of battery it uses, which will probably be a CR2032.

IDE Channels: Here is where you'll find what IDE drives you have connected to your PC. These are the ones that use those old school fat ribbon cables of yesteryear and require multiple drives on the same channel be configured as 'Master' and 'Slave.' Your drives should show up automatically, but if not, highlight the appropriate entry and hit the Enter key, which brings up another submenu.

- IDE HDD Auto-Detection: Use this to auto-detect a newly connected hard drive.
- Access Mode: Also known as the Translation Method, this setting relays the physical characteristics of your IDE drive to your system and how to define the disk size.

If you're still not seeing your drive(s) show up, check that the jumper on the back has been properly configured and that you remembered to plug in a Molex power connector.

SATA Channels: These are your SATA drives, though your motherboard may still label them as IDE. Because each SATA drive operates on its own channel, they do not contain 'Master' and 'Slave' settings. On a related note, only connect ONE power source, even if it has inputs for both a 4-pin Molex and SATA power connectors. Plugging these both in can ruin your HDD.

Drive A and B: Refers to the type (if any) of floppy drive you have installed, or plan to install. The most common today is 1.44M, 3.5 in. You can also set this to Disabled if you're not planning to rock out with your floppy out.

Floppy 3 Mode Support: Designates a special type of floppy drive that supports three different types of floppies. These were mainly used in Japan and never gained any major footing in the U.S.

Video: Some motherboards don't even include this setting anymore, but this allows you to designate what type of videocard you have installed. Unless you have a specialized configuration, this should read EGA/VGA' Set this to your primary videocard type, and not the secondary (if one is installed).

Halt On: Configure this setting to tell your BIOS which errors to ignore during POST.

Advanced BIOS Features

In the Advanced menu, you'll begin to scratch beneath the surface and configure how various parts of your system operate. This might also be where you set the boot priority, though some motherboards -- like those Asus offers -- dedicate a separate submenu to this task.

Hard Disk Priority: When you have multiple hard drives installed, this setting tells your BIOS which order it should attempt to boot them. This can be handy for dual-booting OSes, with each OS -- like Windows and Linux -- installed on separate drives.

First and Subsequent Boot Device: This is where you'll determine what order your system should attempt to boot from. If installing Windows, for example, you'll want to designate your CD/DVD drive as the first boot device before your hard drive.

Password Check: If you set a password, you can instruct your BIOS to ask for it either when booting the PC or when attempting to enter the BIOS.

HDD S.M.A.R.T. Monitor: Short for Smart Monitoring Analysis and Reporting Technology, this serves as a preventative diagnostic to help predict imminent hard drive failures. When enabled, supported hard drives will report any problems that could ultimately lead to outright failures.

Limit CPUID Max. to 3: The only ones who should have this setting enabled are those running a legacy OS with a Pentium 4 processor or higher. CPUID instructions are used to identify the type of processor installed, and the higher the number, the more information can be obtained and written to. Operating systems released before the Pentium 4 had trouble handling the additional CPUID parameters, which is where this limit comes into play. Vista, XP, and Windows 7 users can safely leave this option Enabled.

No-Execute Memory Protect: This safeguard prevents buffer overflow attacks and both AMD and Intel support this feature, it's just labeled differently. When enabled, certain areas of memory will be marked as non-executable, preventing the processor from executing potentially dangerous code in those areas.

Delay For HDD (Secs): Also known as a Hard Disk Pre-Delay, this feature mostly applies to older IDE hard drives. In some cases, older, slower HDDs were incapable of spinning up in time to be intialized, rendering them undectable. To resolve this, motherboard makers introduced a way for users to manually force a delay before this happens.

Full Screen Logo: Rather than display a drab -- and sometimes cryptic - POST screen, enabling this setting will instead display the motherboard manufacturer's boot logo, or Splash screen, if one is included. More than just window dressing, these Splash screens often display helpful tips, such as what button to press to get into the BIOS (most often the DEL key) and how to initialize the motherboard's BIOS update utility.

You only have a few seconds before the Splash screen disappears, and at that point, you can no longer get into the BIOS unless you reboot and try again. Alternately, you can usually whisk the Splash screen away by hitting the TAB key, which will then display the standard POST screen.

Init Display First: In ancient times somewhere around the year 9 BT (Before Twitter), gamer's evolved from using PCI-based videocards to those built for the then-emerging AGP standard. This setting allowed users to tell their systems which type of card they were using, and if improperly configured, could lead to a blank screen. This was mainly relevant when running two types of videocards in the same machine.

Today's gamers get their groove on with PCI-Express based videocards, or at least the serious ones do (it's going to be fun looking back at this comment a decade from now). Most modern motherboards give you the option of selecting PEG, which is your PCI-Express graphics port, or PCI. The latter comes in handy when troubleshooting a potentially bad videocard by sticking a PCI card in your system. If it's not automatically detected, change this setting to PCI.

Integrated Peripherals

Every motherboard comes with at least a handful of functionality embedded into the board itself. When installing a third party peripheral -- like a Creative X-Fi soundcard -- your first order of business should be to the disable your motherboard's onboard equivalent to prevent any conflicts, and this is the section where you'll find those options.

The other school of thought here is that by disabling unused peripherals and ports, you can recover additional resources for improved performance. And for a time, this might have been true. However, now that 2GB and over has become the standard, you're not likely to gain any significant advantages by disabling unused LAN and other dormant ports, but you do run the risk of forgetting you disabled a previously unused port in the BIOS, making you think you have a bad mobo. Keep that in mind before you go disabling everything in sight.

SATA RAID/AHCI Mode: You might not always find this setting under Integrated Peripherals, depending on the layout of your BIOS. It might also be labeled slightly differently, but the options are the same. Here are your three possible choices.

IDE: Often times the default option, this sets up your system so that your SATA drives run in IDE mode (see below).

AHCI: Short for Advanced Host Controller Interface, AHCI takes better advantage of SATA drives by enabling hot swapping and NCQ, but there's a caveat. If you've already installed Windows, suddenly switching from IDE mode to AHCI will quickly muck things up. On the other hand, it's a good way to see what a BSOD looks like if you've never seen one before. Otherwise, be prepared to start fresh with a new Windows installation.

RAID/IDE: As the name implies, choose this when you plan to run one or more drives in a RAID array using your motherboard's built-in RAID controller.

SATA Port 0-3 Native Mode: The most common solution, configuring SATA drives in native IDE mode is also the easiest, as it sports the most compatibility and a 'driver-less' install, at least in terms of not needing to go through the F6 dance. Disabling this option puts the SATA ports in Legacy IDE mode, which is used for pre-XP OSes like Win 9x/ME

USB 1.0 Controller: We don't know why anyone would choose to disable their motherboard's onboard USB controllers, but this would be the place to do it.

USB 2.0 Controller: Also known as EHCI, or Enhanced Host Controller Interface, you'll need to enable this setting to take full advantage of your motherboard's USB 2.0 ports and high-speed USB devices.

USB Keyboard Function: If you don't have this option enabled, it will be difficult (read: impossible) to get into your motherboard's BIOS without a legacy PS/2 keyboard.

USB Mouse Function: Enables USB mouse support for use with OSes that don't support it natively.

Legacy USB Storage Detect: Some very old OSes -- like DOS -- don't play nice with USB storage devices. Enabling this setting can help through emulation.

Azalia Codec: Several onboard audio solutions exist and depending on which one your motherboard manufacture has chosen, so finding this setting might be obvious (Onboard Audio) or a bit obscure (Azalia Codec, AC97). Enable this if you plan to use the included audio chip, and disable this setting if you plan to get your groove on with a discrete soundcard, such as Creative's X-Fi series or Asus' Xonar, to name just a couple.

Onboard H/W 1394: Refers to your motherboard's Firewire port(s).

Onboard H/W LAN: Depending on how many LAN ports your motherboard comes with, you may see one or several different entries (LAN1, LAN2, etc). Keep these enabled if you plan to do any kind of wired networking, including connecting your PC to a DSL or cable modem.

Green LAN: A power saving feature, enabling this option tells your motherboard to disable the network socket and onboard LAN chip when it doesn't detect a connection.

SMART LAN: This performs a diagnostic on your motherboard's integrated LAN ports.

Onboard LAN Boot ROM: Contrary to what you might have guessed, this setting doesn't refer to booting your PC remotely via the LAN port. Instead, this is intended for newer Gigabit LAN ports to operate at their full 1Gbps speed when using an older OS by loading the LAN controller's boot ROM during boot.

Onboard SATA/IDE Device: Enables your motherboard's SATA ports. Go figure!

Onboard SATA/IDE Ctrl Mode: This is where you'll tell your motherboard to operate its SATA ports in IDE, AHCI, or RAID mode, as outlined above (see SATA RAID/AHCI Mode).

Onboard Serial Port: This setting allocates an address and IRQ for your motherboard's serial port. Unless you're experiencing any IRQ conflicts, you should leave this setting on Auto (if it's an option), or however it comes configured by default (typically 3F8/IRQ4). If you don't plan on using the serial port, you can safely disable this setting, freeing up an IRQ in the process.

Onboard Parallel Port: Same as above, use this setting to configure your parallel port, otherwise known as LPT1. Or better yet, retire that crusty dot matrix printer and finally make the jump to a USB-based inkjet printer and never bother with a parallel port again.

Parallel Port Mode: Settings here include SPP (Standard Parallel Port), EPP (Enhanced Parallel Port), and ECP (Extended Capabilities Port). EPP adds bi-directional communications support between the PC and connected devices, resulting in faster transfers and lower CPU usage. ECP supports even faster transfers and is useful for daisy-chaining multiple parallel port devices.

Power Management

With the recent push towards reducing carbon footprints and going green, power management schemes have started garnering a lot of attention. Some basic power saving features have been included on most motherboards for some time now, and this is where you'll find them.

ACPI Suspend Type: Short for Advanced Configuration and Power Interface, this setting dictates what power saving state your system goes into. ACPI replaces the older Advanced Power Management (APM) scheme and requires a compatible OS, such as Windows 98 and up, along with several Linux distributions.

S1(POS): In an S1 state, the CPU stops processing cycles but it, along with the RAM, are still fed power.

S3(STR): Also referred to as Suspend to RAM, this options saves the data to RAM before putting the PC in a sleep state. In most cases, fans and all other devices will be powered down, so it appears as though the PC is actually turned off.

Soft-Off by PWR-BTTN: This lets you adjust how long you need to press the power button before your system turns off. Choosing Instant Off will power off the system instantly, whereas Delay 4 Sec configures it so you need to hold the power button for 4 seconds before powering down. With the latter option enabled, pressing the power button (as opposed to holding it) puts the PC in a suspend state, feeding a small amount of power to the system.

PME Event Wake Up: Short for Power Management Event, this redundantly-named entry is usually the culprit when you find that your PC has turned on during the middle the night even though you remember turning it off before going to bed. Also referred to as Wake on LAN (WoL), network activity or a stray electrical signal tells your PC to fire up if you have this setting enabled.

Power on by Ring: You might also see this entry labeled as Wake/Power Up on Ext. Modem. Enabling this setting tells the PC to turn itself on when a call comes in through a phone line connected to the modem.

Resume by Alarm: Used to specify a time and date of the month (or everyday) for the PC to turn on automatically. Some ITs find this handy for ensuring PCs are up and running on Microsoft's Patch Tuesday, and businesses find it useful for making sure PCs are up and running when employees start rolling in early morning. You might also see this entry labeled Resume by RTC (Real Time Clock) Alarm.

HPET Support: Short for High Precision Event Timer, Microsoft describes this as a "new system timer that is needed in chipsets to replace legacy timers and to meet the needs of time-sensitive applications." By enabling this feature, the company claims system performance is improved.

HPET Mode: You can set this to either 32-bit or 64-bit, depending on your operating system. If you're rolling with a 64-bit OS, choose the latter to take full advantage of HPET's 64-bit registers.

Power on by Mouse: Enables turning on the system with a double-click.

Power on by Keyboard: Enables turning on the system by pressing your keyboard's Power key. Additionally, some BIOSes allow you to setup a short password instead of pressing the Power button. If setting up a password, you'll need to mash the Enter key afterwards.

AC Back Function: Also referred to as AC Power Loss Restart, this setting dictates how your PC responds to an unexpected power loss once the power is restored.

Soft-Off: Leaves the PC turned off, even if it was turned on prior to losing power.

Full-On: Turns the PC back on following a power loss.

Memory: If the PC was turned on prior to losing power, it will boot back up once power is restored. But if the PC was off to begin with, it will remain turned off.

Advanced CPU Features

Gigabyte's latest boards clumps these entries together in a handy submenu, but depending on your make and model, you may find these settings spread out in different sections of your BIOS.

CPU Clock Ratio: Otherwise known as the multipler, this number multiplied by your CPU's base frequency determines your processors clockspeed. See chipset-specific BIOS options below.

Intel Turbo Boost Tech.: New to Nehalem (Core i7), enabling this feature will temporarily boost processor cores to run faster than their stock frequency depending on the current power, current, and temperature levels.

CPU Cores Enabled: Allows you to enable all or just some of your processor's cores.

CPU Multi-Threading: Enable this option to take advantage of Intel's HyperThreading technology.

CPU Enhanced Halt (C1E): A power saving feature in Intel chips, enabling C1E will allow the operating system to send a halt command to the CPU when inactive. This halt state reduces both the processor's voltage and multiplier so that it consumes less power and runs cooler. This doesn't affect performance, though some power users have noted better overclocking headroom when disabling this setting.

C3/C67/C7 State Support: Essentially a revised version of C1E, these higher-numbered halt states put the processor into an even lower power state when idle. Again, overclocking results may vary, but performance does not.

CPU Thermal Monitor: First introduced with the Pentium 4, current iterations take a somewhat different approach by dropping down the core clockspeed and voltage when things get a bit too hot under the collar.

CPU EIST Function: Short for Enhanced Intel SpeedStep, this power-saving setting allows Intel chips to dynamically change frequency and voltage levels in small increments based on need.

Virtualization Technology: Enabling this feature allows virtualization programs like VMWare and Virtual PC to tap into your processor's hardware virtualization support

Bi-Directional PROCHOT: Enabling this setting sends a bi-directional signal that indicates if the processor has exceeded its maximum temperature and whether or not it should activate the Thermal Control Circuit (TCC).

PnP/PCI Configurations

This is the section of the BIOS that deals with the PCI bus and Plug-and-Play settings, most notably IRQ mapping. Unless you're attempting to run legacy hardware or are running into troubleshooting issues with your PCI peripherals, you won't be spending much time, if any, in this section.

PCI1 and PCI2 IRQ Assignment: This lets you configure whether to let your PC dole out IRQ resources automatically or to let you configure them manually. Unless you're dealing with older hardware or niggling IRQ conflicts that are not resolved by moving PCI cards to a different PCI slot, you should leave this one on Auto.

PC Health Status

On most Asus boards, this section will come labeled as a Hardware Monitor submenu in the Power section. MSI boards usually call this H/W Monitor accessible through the BIOS's main menu. In each case, this is where you'll find system vitals, such as current system and CPU temperatures, fan speeds, and various voltage levels. This is helpful when troubleshooting overheating issues or power issues, such as random reboots, but treat this as a starting point before digging deeper. Overheating due to a poorly installed heatsink, for example, might not manifest itself until you boot into Windows and encode a DVD or otherwise stress your CPU.

Recent Case Open Status: Only of use with compatible cases, this security feature can detect if your case has been opened and reset the status at the next boot.

CPU Warning Temperature: Sounds an alarm when a certain CPU temperature threshold is reached.

CPU Fan Fail Warning: Sounds an alarm should the CPU heatsink's fan stop spinning, or whichever fan you have plugged into your motherboard's CPU fan power header.

System Fan 2 Fail Warning: Sounds an alarm when the fan plugged into this header stops spinning.

Power Fan Fail Warning: Sounds an alarm when the fan plugged into this header stops spinning (seeing a pattern yet?).

System Fan 1 Fail Warning: Sounds an alarm when...you get the idea.

CPU Smart Fan Control: Disabling this setting allows the CPU heatsink's fan to run at full bore all the time. Enabling this setting will vary the fan speed depending on CPU temperature.

CPU Smart Fan Mode: If you enable CPU Smart Fan Control, you can then set the mode to Auto (controlled by the BIOS), Voltage (for use with 3-pin fans), or PWM (for use with 4-pin fans).

DRAM Timing

If your motherboard allows you to manually tweak your RAM's latency timings, you'll find them in the overclocking section. These will most often be labeled as MB Intelligent Tweaker (Gigabyte), Cell Menu (MSI), Advanced Chipset (Asus), or Genie BIOS Setting (DFI). Other overclocking options will also be available, but we'll focus on these in more detail later on.

Performance Enhance: Applicable to Gigabyte boards, this section tells the BIOS how aggressively to auto-tune your RAM's settings.

Extreme Memory Profile (X.M.P.): Short for eXtreme Memory Profile, X.M.P.-compatible RAM contain additional, pre-programmed settings tuned for both performance and overclocking.

System Memory Multiplier: Left on Auto, your BIOS will determine the safest multiplier, or FSB:DRAM ratio, and resulting memory frequency for your RAM based on its pre-programmed SPD settings. If overclocking or tuning for additional performance, you can manually set the multiplier.

DRAM Timing Selectable: You may see the letters SPD in this section. This stands for Serial Presence Detect and refers to the information programmed into your memory modules by the manufacturer, which tells the BIOS what latencies and voltage to use at any given clockspeed to ensure compatibility. If left on Auto, your RAM will run at its pre-programmed SPD settings when overclocking. Otherwise, you can change this to Manual (or disabled) to and set your own latency timings.

Channel A/B/C Timing Settings: Refers to your RAM's timings or latencies, separated by memory channel.

CAS Latency Time: Short for Column Address Strobe, this number dictates the number of clock cycles that pass before data can be read or written to from where it's stored in a column address. The lower the number, the faster this takes place. When shopping for memory modules, the CAS latency is typically the first of a set of four numbers (for example, 8-8-8-24).

tRCD: Also referred to as DRAM RAS# to CAS# Delay, this number represents the delay in clock cycles it takes to find the fow of a location in memory and finding the column. The lower the number, faster this takes place. When shopping for memory modules, RAS# to CAS# is typically the second number in a set of four (for example, 8-8-8-24).

tRP: Also referred to DRAM RAS# Precharge, the RAS precharge is how long it takes for the memory to stop accessing one row, build up a charge, and access another. The lower the number, the fast this takes place. When shopping for memory modules, RAS# Precharge is typically the third number in a set of four (for example, 8-8-8-24).

tRAS: Also referred to as Precharge Delay, this number represents the minimum number of cylces that pass between an active and precharge command. The lower the number, the faster the performance. When shopping for memory modules, the Precharge Delay is typically the last (and highest) number in a set of four (for example, 8-8-8-24).

Command Rate (CMD): The Command Rate is the delay, in clock cycles, from when a memory chip is selected to when the first active command can be sent. A 1T command rate offers better performance than 2T, but if you experience instability, you'll want to change this 2T.

Advanced Timing Control: Depending on your motherboard, you may find anywhere from a handful to a boatload of additional RAM timings. These refer to various other dealys and can be overwhelming to even experienced overclockers. Unless you're shooting for a record overclock or trying to get over a certain MHz bump, we recommend leaving these settings on Auto.

Channel A/B/C Turnaround Settings: These submenus control the read and write delay settings, again separated by channel.

Overclocking

If you're going to overclock, you first must understand the nomenclature that applies to your processor and motherboard chipset's architecture. To help you do this, we rounded up three different motherboards each one based on a different, recent architecture.

Check out our Core 2 Overclocking Guide here

Intel P45 Chipset

The settings below also apply to Intel's X38 and X48 chipsets, and in some form even date back several generations. We used an Asus Formula Maximus II for this section.

Ai Overclock Tuner: Many enthusiast motherboards come with some form of automatic overclocking, and Asus calls its version the Ai Overclock Tuner.

Manual: Just as it says, choose this option if you plan to manually overclock your system.

Auto: Somewhat misleading, this really should be called Disabled. But despite the goofy nomenclature, leaving this setting on Auto tells the BIOS not to automatically overclock your CPU.

CPU Level Up: This option will attempt to automatically overclock your processor to that of a higher end chip. Or in other words, level up. Get it?

Ratio CMOS Setting: Also known as the CPU clock ratio or, more commonly, the CPU multiplier, you'll find this setting on both AMD and Intel processors. The multiplier measures the ratio of an internal CPU clock rate to an externally supplied clock often called the frontside bus and is used to determine your CPU's clockspeed. For example, an E8400 processor ships with a 9X multiplier and a 333MHz base clockspeed. Multiplied together, you arrive at 3.0GHz (3,000MHz). Intel locks the multiplier on all but its Extreme Edition CPUs, which prevents end-users from increasing the multiplier, but not from decreasing it.

CPU Clock Skew: At the blistering speed that today's components operate at, timing issues can rear their ugly heads when trying to communicate with each other and result in instability, particularly when overclocking. To keep the different parts working in sync, some motherboards -- such as this one -- allow you to introduce tiny delays in different subsystems of your PC. In this case, you're 'skewing' the speed of the CPU clock as measured in picoseconds (ps), or one trillionth of a second.

NB Clock Skew: Allows you to introduce a delay to the Northbridge controller.

FSB Strap to North Bridge: This setting determines what memory divider ratios will be made available. Since the DRAM's frequency is linked to the frontside bus, dividers can help you achieve a higher CPU overclock without taxing the memory. Dividers available by FSB Strap include:

200 (5:3, 2:1)
266 (5:4, 3:2, 2:1)
333 (1:1, 6:5, 8:5, 2:1)
400 (1:1, 4:3, 3:2, 2:1)

DRAM Frequency: This determines the frequency of your RAM. The settings available will depend on what FSB Strap you selected (see above).

DRAM Clock Skew: Allows you to introduce a delay to the individual RAM slots to address timing issues. See CPU Clock Skew above.

DRAM Timing Control: Lets you select whether you want the BIOS to automatically set your RAM's timings or if you want to manually input them yourself. See DRAM Timing for more information.

DRAM Static Read Control: This setting influences the overall memory access latency. In theory, enabling this setting can increase memory bandwidth.

DRAM Read Training: Like the skew settings, this option supposedly optimizes DRAM timing.

Mem. OC Charger: Intended to improve signal quality and, as a result, improve overclocking potential, not all memory modules play nice with this setting. And for the ones that do, Asus cautions not to expect any miracles.

Ai Clock Twister: Used in conjunction with the Ai Overclock Tuner, this setting determines how aggressive the board will attempt to run your memory's latency timings.

Ai Transaction Booster: Also known as Performance Level, this setting automatically adjusts parameters of the chipset to improve performace. The lower the number, the better the performance.

CPU Voltage: No big mystery here. As the name suggests, this is where you can adjust how much voltage gets pumped into your processor. Safe amounts will vary by processor, and even by different steppings of the same CPU, so be sure to thoroughly research before mucking with this setting.

CPU PLL Voltage: Determines the voltage applied to the CPU's internal clock generators. Overvolting this setting is a quick way to send your processor to the grave.

FSB Termination Voltage: This controls the voltage at the end of the frontside bus on the termination buffers. Increasing this can help with overclocking, however it also can result in instability, higher temps, and damage to your CPU.

DRAM Voltage: Determines the voltage for your memory modules. Safe amounts will vary by make and model. Generally speaking, DDR2 starts to get pretty hot at 2.3V and above and may require active cooling. Do your research and consult your memory kit's specs before manually adjusting the voltage.

North Bridge Voltage: Controls the voltage for your board's Northbridge (minus 1,000 geek points if you couldn't guess this one).

South Bridge 1.5 Voltage: Controls the voltage for the 1.5V line in your board's Southbridge, which is tied to the PCI-E bus.

South Bridge 1.1 Voltage: Controls the voltage for the 1.1V line from the Southbridge to the Northbridge, otherwise known as the base chipset voltage.

CPU GTL Reference: These setting represent advanced voltage options for the CPU's Gunning Transceiver Logic (GTL), which is an open drain, low power switching circuit. You can read more than you probably want know about the GTL here.

NB GTL Reference: Same as above, only in regards to the Northbridge.

DDR2 ChA Reference Voltage: Allows you to individually tweak the voltage levels for each memory bank (not to be confused with each memory slot).

North Bridge DDR Reference: Provides a fixed voltage to the memory bus and can presumably help with stability.

Load Line Calibration: Enabling this setting stabilizes voltage levels during both idle and load, reducing or eliminating vdroop altogether.

PCIE Spread Spectrum: Limits the electrical interference so that it stays within the FCC limit.

AMD 790FX Chipset

Starting with the Athlon 64, AMD moved away from a traditional frontside bus architecture in favor of using an integrated memory controller and a HyperTransport bus. This meant learning new terms and new ways of overclocking. We used a Gigabyte Ga-MA790FX motherboard for this section.

Advanced Clock Calibration: Advanced Clock Calibration, or ACC, taps into previously unused pins on Phenom processors for use with the chipset's Southbridge. Through some sort of guarded voodoo magic, this unlocks higher overclocking potential and is exclusive to Phenom processors.

CPU Clock Ratio: Also known as the Ratio CMOS Setting (P45 chipset) or, more commonly, the CPU multiplier, you'll find this setting on both AMD and Intel processors. The multiplier measures the ratio of an internal CPU clock rate to an externally supplied clock often called the frontside bus and is used to determine your CPU's clockspeed. For example, a Phenom 955 processor ships with a 16X multiplier and a 200MHz HyperTransport reference clockspeed. Multiplied together, you arrive at 3.2GHz (3,200MHz).

CPU Northbridge Frequency: Contains multiplier settings for the Northbridge frequency. This number multiplied by the HT reference clock equals the Northbridge frequency.

CPU Host Clock Control: It's a shame motherboard makers don't label their BIOSes more intelligently. If they did, this option would simply be labeled 'Do You Wish to Overclock Manually?' By enabling the CPU Host Clock Control, you're answering 'Yes' to that question and the appropriate settings are then unlocked.

CPU Frequency: Otherwise known as the base frequency or HT frequency, this number multiplied by the CPU multiplier gives you the processor's clockspeed.

PCIE Clock (MHz): Allows you to set the clockspeed for (and overclock) your PCI-E graphics port.

HT Link Width: This is where you designate the width of the HyperTransport interconnects, which directly affects the maximum theoretical bandwidth. The Link Width is bi-directional.

HT Link Frequency: Don't let the nomenclature fool you - this is really the HT Link multiplier. When multiplied by the HT reference clock, you arrive at the HT Link clockspeed.

DRAM Configuration: Inside this submenu sits all the options for tweaking and overclocking your memory. Let's take a look at some of the less obvious entries.

DCTs Mode: Unofficially short for Dual-Channel Type, you have two choices: Ganged and Unganged. A common misconception is that Unganged operates in single-channel mode, but this isn't the case. In Ganged mode, each memory subsystem is treated as a single 128-bit dual-channel bus, whereas Unganged treats each memory subsystem as two independent 64-bit dual-channel buses. In most cases, Unganged offers better bandwidth and performance.

Set Memory Clock: This is where you either tell the BIOS to automatically configure your RAM's clockspeed or to let you manually adjust it.

DCT Channel Interleave: Describes whether or not memory is accessed as a single, large block to act as a single module (Enabled).

System Voltage Control: Enable this setting if you plan on manually inputting your system's different voltages.

DDR3 Voltage Control: Allows you to adjust your RAM's voltage level. Consult your kit's rated specs, as pumping too much voltage can kill your memory.

SB/HT Voltage Control: Voltage settings for the Southbridge and HyperTransport.

NB/PCIe/PLL Voltage Control: Voltage settings for the chipsets' power regulation circuits all inconveniently bundled together.

CPU PLL Voltage Control: Determines the voltage applied to the CPU's internal clock generators. Overvolting this setting is a quick way to send your processor to the grave.

DDR VTT Voltage Control: Determines the termination voltage for your system's RAM. Raising the VTT increases the current flow and can help increase stability.

NB Voltage Control: Voltage settings for the Northbridge chipset.

CPU NB VID Control: Voltage settings for the memory controller on the CPU. This can help with stability when overclocking.

CPU Voltage Control: Voltage settings for the processor.

Intel X58 Chipset

With the introduction of Nehalem -- now better known as Core i7 -- Intel moved away from a traditional frontside bus architecture in favor of an integrated memory controller, somewhat similar to what AMD had been using for years. This also meant that old hats at overclocking suddenly were forced to learn new terms. For this section, we used an Asus Rampage II motherboard.

Check out our Core i7 Overclocking Guide here

Ai Overclock Tuner: As previously stated (see Intel P45 Chipset), this is Asus' implementation of automatic overclocking.

OC From CPU Level Up: This option will attempt to automatically overclock your processor to that of a higher end chip. Or in other words, level up.

OC From Memory Level Up: This option will attempt to automatically overclock your memory to that of a higher end kit. Or in other words, level up.

CPU Ratio Setting (MSI - Adjust CPU Ratio, Gigabyte - CPU Clock Ratio): Also known as the CPU Clock Ratio or, more commonly, the CPU multiplier, you'll find this setting on both AMD and Intel processors. The multiplier measures the ratio of an internal CPU clock rate to an externally supplied clock often called the frontside bus and is used to determine your CPU's clockspeed. For example, a Core i7 920 processor ships with a 20X multiplier and a 133MHz base clockspeed. Multiplied together, you arrive at 2.67GHz (2,667MHz). Intel locks the multiplier on all but its Extreme Edition CPUs, which prevents end-users from increasing the multiplier, but not from decreasing it.

CPU Turbo Power Limit: Enabling this setting prevents the Turbo mode ratio from changing based on CPU load. For this to work, both C1E and TM functions must also be disabled.

BCLK Frequency (MSI - Base Clock, Gigabyte - Base Clock Control): Intel's new architecture whisked away the traditional frontside bus so many Intel fans had grown up on, and replaced it with a base clock, or bclock (or in this case, BCLK). You may also see this referred to as a host clock or reference clock. Core i7 processors come with a base clock of 133MHz, and the easiest way to overclock is by pushing this frequency higher. However, you'll also be overclocking other subsystems, such as the RAM and uncore.

PCIE Frequency: Allows you to set the clockspeed for (and overclock) your PCI-E graphics port.

DRAM Frequency (MSI - Memory Frequency, Gigabyte - System Memory Frequency): As you might have guessed, this is the your RAM's frequency. As you increase the base clock, so too will your DRAM frequency increase.

UCLK Frequency (MSI - Uncore Ratio, Gigabyte - UnCore & QPI Features): This setting controls the speed of the uncore, which describes the areas outside of the Core i7's processor core (integrated memory controller, L3 cache, Quick Path Interconnect).

QPI Link Data Rate (MSI - QPI Configuration, Gigabyte - QPI Link Speed): Short for Quick Path Interconnect, this is the high-speed interface that connects the processor to the chipset. You'll need to keep an eye on this when overclocking, as just like the HyperTransport bus, if the QPI is set too high, you'll find yourself running head first into an overclocking wall of defeat.

EPU II Phase Control: A power saving feature built into some Asus boards, the Energy Processing Unit (EPU) dynamically adjusts voltages based on load, and can also hinder potential overclocks.

CPU Differential Amplitude: Some Asus boards allow you to increase the amplitude of the differential clock signals making them less susceptible to noise. Asus claims this can also help achieve a higher base clock frequency.

Extreme OV: Not for the faint of heart, enabling this setting allows you to 'OverVolt' higher than you would normally be able to. Air cooling aficionados need not apply.

IOH Voltage: For overvolting the Northbridge.

IOH PCIE Voltage: For overvolting the PCI-E bus.

ICH Voltage: For overvolting the Southbridge.

DRAM Bus Voltage: For overvolting the memory bus.

When and Why to Update the BIOS

Updating or flashing the BIOS carries a certain amount of risk, but the potential rewards make it worth the effort. Motherboard makers are contstantly enhanching the BIOS firmware and the end result can be significantly improved performance, less buggy behavior, additional functionality, improved overclocking performance, and much more.

BIOS updates can also be minor and only address a specific function, such as adding native support for higher frequency RAM or a new CPU stepping. If the added functionality isn't something that affects your setup, you needn't worry about updating your BIOS. The general rule of thumb is if it isn't broken, well, you know the rest.

We recommend checking your vendor's website every few months to see if any new BIOS versions have been released, and if so, what changes they bring. Then make a determination on whether or not you should flash your BIOS.

Precautions

You've heard of Murphy's Law, and it definitely applies here. While BIOS flashes have become orders of magnitude easier and less risky in recent years, the one time you attempt to update your BIOS unprepared will inevitably be the time something goes wrong.

Standard housekeeping applies - backup any important data. A BIOS flash won't nuke your hard drive, but if done incorrectly, it could kill your motherboard. Plus, you should have a routine backup plan in place anyway.

Next, tune your system for stability. If you're overclocking, revert back to default clockspeeds and voltage levels. The reason for this is because if there's an underlying instability issue -- even one you're not aware of -- your system could suddenly reboot during the middle of a BIOS flash, rendering your BIOS chip corrupt and your motherboard a rather bulky keychain.

Finally, make a note of any pertinent BIOS settings that you've changed from their default values. Sometimes when updating the BIOS, all settings are reverted back to default. Did you disable onboard sound? You may need to do so again.

Windows BIOS Update Utilities

Most motherboard manufacturers offer some kind of handy Windows utility with a snazzy GUI for updating your BIOS. If at all possible, avoid using these, particularly if you're updating your BIOS because of instability. Should your Windows installation suddenly freeze or restart, you could be in a world of trouble.

How to Update

There are several alternative methods to updating your BIOS, the simpliest being from a USB key. Some motherboard manufacturers implement a built-in utility for updating the BIOS during POST. Gigabyte boards, for example, come with a Q-Flash utility. To use it, you would first go to your motherboard's product page and download the latest BIOS file (when updating a BIOS, you don't need to go in order - you can skip straight to the latest BIOS version) and copy it to your USB key. Next, reboot your PC and hit the End key during post or F8 from within the BIOS. This brings up the Q-Flash utility. Follow the GUI prompts to locate and load the BIOS on your USB key and sit back while the new firmware is written. Be sure not to power down or reset your system.

Q-Flash (Gigabyte)

EZ-Flash 2 (Asus)

If you own an older or proprietary system, you may need to kick it old school and update your BIOS with a floppy disk using one of several utilities. Reference your motherboard maker's website to see which utilities your motherboard supports (see here, for example).

Check out our Essential BIOS Tweaking Guide here!

Core 2 Overclocking Guide

Core i7 Overclocking Guide

Rumor: Intel to Release Six Core Nehalem in 2009

Paul Lilly — Fri, 12 Jun 2009 09:00:22 -0500

File this one under unconfirmed, but word on the web is that Intel plans to release a six-core Nehalem chip before the end of the year. Citing "sources close to Intel," Bit-tech says existing X58 motherboard owners should be able to drop the new chip into their motherboard with only a BIOS update, giving current Core i7 owners a tantalizing upgrade path to look forward to.

Not much else is known about the supposed six-core Nehalem, however those same sources did say the new chip won't fall into the Core i7 naming scheme. The name is still being worked out

Should this come to fruition, Intel would be the first to market with a six-core consumer desktop CPU. AMD earlier this month released a six-core part well ahead of schedule, but it's a server chip and not a desktop part. Intel also has an existing six-core processor in Xeon form, also intended for servers.

Revised TPower X58A Motherboard Now Available, Biostar Makes Quirky Pitch for Core i7 Platform

Paul Lilly — Tue, 19 May 2009 09:29:34 -0500

Biostar's second Core-i7 compatible motherboard, the TPower X58A, is now available for sale, and here's why the company believes you should look at upgrading to the platform, price be damned.

"Although Intel X58 chipset based motherboard is sold at a relatively higher price in the market, Biostar still has an excellent reputation for TPower series, in which TPower X58 and TPower I45 are very popular with a lot of power users," Biostar writes in its press release.

Alrighty then. But quirky marketing aside, the revised TPower X58A does come with some enthusiast features, such as adopting an overclocker-friendly 12+2 power phase design (12-phase CPU and 2-phase memory), Ferrite core chokes, all Japananese manufactured solid capacitors, support for up to 24GB of DDR3-1333/1600/2000, three PCI-E 2.0 x16 slots, eSATA support, and a 'Rapid Debug 3' POST LED display to help you figure out which device(s) might be failing.

It's worth noting that Biostar has made a major push in the past 12 months to shed its reputation as a budget option and compete at the high end, snagging overclocking and frontside bus world records along the way.

The X58A streets for around $240.

Asus Rampage II Extreme

Gordon Mah Ung — Mon, 06 Apr 2009 15:00:00 -0500

To run Asus’s $400 Rampage II Extreme board you’d have to be either extreme or the world’s biggest poseur. How extreme would you have to be? You’d have to be the type of person who boils liquid helium atop his CPU to keep it cool. And because you can’t waste time overclocking from within the OS, you’d want to reach your hands into the guts of your case and use the board’s PCB-mounted controls that let you check and change voltage, fan speeds, and temps on a tiny one-line LCD external display.

In fact, you’d be so damn hardcore, you wouldn’t even fully trust those voltage readings from the board. Instead, you’d want to hook your Fluke meter directly to the available ports on the board to check the voltage of the CPU, the PCI Express lanes, and the north bridge directly. That’s how badass you’d be.

OK, but what if you’re just a poseur? Don’t worry, you’re set, too. Just fire up the OS applet, set your 3.2GHz Core i7-965 to “i7-crazy-4.0,” and you’re good to go. Now people will think you’re an extreme overclocker when all you did was let the board do the work for you.

Whether you’re a poseur or an extremist, the Rampage II Extreme has everything you need, including six DIMM slots, tri-SLI, and CrossFireX support, as well as licensed Creative audio support that gives you up to EAX4. There are some problems, however. Our biggest issue is that Asus still can’t seem to get Turbo mode to work correctly. You should be able to set Turbo mode based on the thread load on the CPU, but Asus only lets you overclock all cores simultaneously. We also felt overwhelmed by the applets on the board. Between the controls for AI Suite, TurboV, TweakIt, and EPU-6, we couldn’t keep straight what each tool did, and ultimately ignored them all.

As we’ve noted in previous reviews, differences in how motherboard vendors treat their BIOSes and Core i7 overclocking options make it difficult for us to run an exact apples-to-apples comparison among boards. For what it’s worth, though, the Rampage II Extreme fell right into the middle of the pack in our benchmarks. With BIOS updates for i7 boards arriving on a monthly schedule, it’s clear that third-party boardmakers are still trying to get a handle on the brave new world of Core i7.
So, say you’re not that extreme nor do you want to appear to be, well then, we think you’re probably better off with a different, less expensive board.

Exclusive: Retail Core i7 CPUs More Powerful than Originally Reported

Gordon Mah Ung — Wed, 04 Mar 2009 22:00:00 -0600

If you’ve tried to research the differences between Intel’s top-end Core i7-965 Extreme Edition and the midrange 940 and budget 920 parts, you’re probably as confused as us. And we even have direct access to Intel. But the technical differences between these parts are enormously important for system builders when you consider the price disparity -- $1000 for a Core i7-965 compared to under $300 for a Core i7-920.

What we do know is that the Core i7-965 has unlocked multipliers going up and down (although we have to point out that we have not seen any motherboards with multipliers that let you actually set it higher. You can only do that by increasing the Turbo Mode ratio.)

One other known fact is that you cannot set the Turbo Mode ratios on the 940 and 920. OK fine. But what else is different? Intel told us as recently as two months ago that the QPI was locked at 4.8GT/s to prevent you from running it at the Extreme’s 6.4GT/s speed. Memory ratios, however, are supposed to be unlocked.

But maybe not.

Our experience with no fewer than three Core i7-920 and 940 chips said otherwise. On these chips, even though you could set the ratio manually in the BIOS for DDR3/1600 or DDR3/1333, the RAM was actually locked at DDR3/1066. We also verified on these chips that the QPI was locked t 4.8GT/s and we had no access to the Turbo Modes. Right, so no Turbo Mode settings, locked QPI and locked memory. Got it, check. Move along.

So where’s the mystery? We recently acquired a retail, boxed Core i7-920 CPU. It was used for a photo shoot and was subjected to extreme heat and smoke damage and had a set of car jumper cables clamped to it. Dead right? Actually no. The processor functions fine but in messing with it, we discovered that the memory ratios were unlocked. Set the RAM at DDR3/1600 and it actually runs at that speed! What the hell? Did we somehow find the secret to unlocking Intel’s Core i7 – just hook it up to car jumper cables? We wish.

With an engineering sample 920 in place, you have but one QPI speed available but populate the board with a production 920 and voila, you get three choices.

After talking with Intel as well as some back channel contacts we had, we learned that the memory multipliers on production CPUs are unlocked. The reason our CPUs had locked multipliers, we were told by Intel, was because they are engineering sample chips. Engineering sample parts are pre-production CPUs provided to the media, OEMs, motherboard makers and various other hardware vendors to test and bring up components. These CPUs, we were told, are locked.

Huh? To make matters worse, while mucking with our retail Core i7-920, we discovered that our QPI speeds were also unlocked. We could set it to 6.4GT/s all day. Our back channel contact tells us that after some digging, it was discovered that yes, that’s the way it’s supposed to be. QPI is supposed to be 4.8GT/s but you can run at it 6.4GT if you want. Wha, what? But two months ago, Intel insisted that QPI was locked. Now we’re told that QPI is unlocked. Confused? We are.

But why lock them, and only on engineering sample parts? Traditionally, Intel’s engineering parts are unlocked so vendors can perform various tests. This is why engineering sample parts sometimes have higher values: they often have no artificial limiters on them.

Intel’s official reason for the change of heart is: “We made a marketing decision to unlock them for the launched product due to requests from some of our customers.”

Who are the customers? Intel didn’t name names but our first guess was memory makers. If memory support for DDR3/1600 was only limited to $1,000 CPUs, they wouldn’t sell a lot of high-end memory. Perhaps some OEMs even balked as well at the thought of selling machines with RAM limited to DDR3/1066.

Even though the board lets you set a memory ratio of 6 for DDR3/1600, it’s not running at that speed.

That’s evident if you look at the POST screen. Here you can see that the RAM is still running at DDR3/1066.

Ultimately we don’t know why Intel decided to do it this way but at least the results helps out the budget buyer and frankly, makes the budget parts even more attractive. So, to sum up, Core i7-920 and Core i7-940 parts have:

Locked multipliers so you cannot exceed their rated top speed (without overclocking the base clock).
Locked Turbo Mode multipliers so you cannot make fine-grained adjustments to the Turbo Mode features.
Have unlocked QPI speeds but are officially rated for 4.8GT/s.
Have unlocked memory multipliers so you can select from 1066/1333/1600/1866 and up.

The board doesn’t seem to know the difference between a locked or unlocked memory multiplier as the production 920 memory ratio setting looks exactly the same.

But reboot and it’s obvious that it is working as it is intended. Here the POST screen shows tri-channel at DDR3/1600 speeds.

Hopefully this helps clear up some confusion around this. If you’re still not sure that your RAM is operating at speed we recommend that you first double check the RAM multiplier in the BIOS and that it is set for, say DDR3/1600. Then download CPUZ from cpuid.com and click on the memory tab. Finally, download a memory benchmark such as Sisoft Sandra and make sure that gives you the result you’re expecting. If you find that Sandra does not show any increased bandwidth going from DDR3/1066 to DDR3/1600, your CPU has a locked memory multiplier and is simply ignoring what your motherboard’s BIOs is saying. In this situation, you’ll want to take it up with the vendor who sold you your CPU.

As final proof, we see that the DDR3/1600 speeds show up in Everest Ultimate and CPUID shows that the RAM is running at speed.

Ultimate Core i7 Overclocking Guide -- We Push Nehalem to its Limits

Gordon Mah Ung — Thu, 05 Feb 2009 12:00:00 -0600

Here’s everything you need to know about overclocking Intel’s new CPU

Overclocking can kill your CPU. It can corrupt your OS, melt your motherboard, and cause you to lose a month’s work or more. Despite those dire orange-alert warnings, however, overclocking has moved on from the Nerd’s Only Club to become practically a mainstream hobby in the last few years.

So why overclock if the risks are so great? For some folks, it’s about bragging rights. Like drag-strip racers who burn up an engine just to set a quarter-mile record, there’s a small community who will overclock a CPU to the brink of destruction just to run a benchmark and take a screen shot of the result.

The bulk of overclockers, however, are more concerned with the cost dividends. If you can take a $300 CPU and make it as fast or faster than one that costs $1,000, the money you save can go toward other components in your system. For these folks, it’s like getting a free high-end videocard.

Whether you’re a cheapskate or a drag racer, you’ll find that Intel’s new Core i7 CPU is unlike any previous Intel CPU, and overclocking this beast requires more tinkering than you might expect. Follow along as we explore what it takes to push this chip hard.

A Brave New World -- The crumbling of the front-side-bus wall means a wholesale change in how you overclock Intel’s top parts

Veteran Intel overclockers know that little about the process changed since the beginning. Like the basics of flying (stick, rudder, ball), all you had to worry about with an Intel processor was the front-side bus, clock multiplier, and core voltage.
Not so with Core i7. With Intel retiring the front-side bus, you’ll need to brush up on your overclocking skills and concepts if you want to get the highest-performing overclock out of the Godzilla of CPUs.

The Base Clock

If you haven’t kept up on current events, you need to know that Intel eliminated the front-side-bus architecture that has connected the CPU to the core-logic chipset since 1978. The memory controller, which used to sit in the chipset, is now integrated directly into the CPU.

Go into the BIOS on a Core i7 and you won’t see any reference to the front-side bus. Instead, it’s now the base clock or bclock. Some BIOSes also refer to this as the host clock or reference clock. On the current i7 procs, the base clock is 133MHz. While it’s not a front-side bus, most overclocking methods will require that you tweak the base clock just as you did with older FSB-based Intel chips and push it beyond 133MHz. One important thing to remember about the base clock is that it is the main reference clock for other components in the CPU— goosing this one setting will also overclock the RAM as well as the “uncore” (i.e., the L3 cache, memory controller, and Quick Path Interconnect, or QPI). We’ll get to more on this shortly.

Doing the Math

One thing that has not changed at all is the multiplier. The Core i7-965 Extreme Edition features a multiplier of 24 and is unlocked so you can move it up or down. The budget Core i7-920 features a multiplier of 20 and is upwardly locked so it will not move past 20. Experienced overclockers can grab a hall pass and skip to the next section, while those who have never done this before will need to stay in the classroom. As it was with the Core 2 and Pentium 4, the overall clock speed of the CPU is derived by multiplying the base clock (formerly the FSB) by the multiplier. For the 965, take 24 and multiply it by 133 to get 3200MHz or 3.2GHz. For the 920, take your multiplier of 20 and multiply by 133 to get 2667MHz or 2.66GHz.

Turbo Talk

One wrinkle to the multiplier is the new Turbo Mode. This mode essentially automatically overclocks a single core of the CPU under certain loads. If you have overclocked a Core i7-920 to 3.66GHz and then you switch on Turbo Mode, the CPU will actually run at 4.03GHz in single-threaded apps. Is it worth it? Frankly, we’re not sure. We are getting to the point where it’s pretty rare to be running performance-intensive single-threaded applications, so the performance boost will be minimal. You do get a 1x multiplier boost in dual-threaded apps so you most games would run at 3.83GHz. Sounds good right?

Our engineering sample Core i7-920 gave us results in line with what others have achieved with engineering sample parts as well as retail parts.

Unfortunately you can’t set your individual Turbo Mode settings on the cheap chips. Intel limits fine-grain Turbo Mode control to the Core i7-965 Extreme Edition. The pedestrian Core i7-920 and Core i7-940 are limited to a single multiplier increase for single-threaded apps, which is of marginal usefulness. It’s also clear that not all motherboard vendors think Turbo Mode is worthwhile. We’ve tested two different Asus boards that don’t implement Turbo Mode the same way Intel does. Instead of letting the user set the individual Turbo Mode settings on an Extreme Edition chip, your only option is to overclock all cores simultaneously.

Turbo Mode is something that should be evaluated based on your needs and the specifics of your overclock. For example, our case study actually found that a moderate overclock with Turbo Mode gave us better benchmark results than a higher-speed overclock without Turbo Mode.

Uncore: Separate but Connected

The Core i7 is a modular design with two main areas, the “core” and the “uncore”. Inside the chip, the actual execution cores that do the heavy lifting are treated as the “core.” The other parts, such as the integrated memory controller, L3 cache, and the Quick Path Interconnect are treated as the “uncore.” Since they’re separate entities, you can overclock the execution cores without overclocking the uncore to the same degree, in theory. This should let you hit higher speeds, since you wouldn’t be running the QPI, memory controller, or L3 quite as hard. In reality, however, it doesn’t work that way. Intel’s non-Extreme Edition Core i7 CPUs offer limited control over the uncore multiplier, so a boost to the base clock boosts the uncore speeds as well.

You need to set your Uncore multiplier to at least twice the multiplier for the system RAM. Also pay attention to the memory voltage. We had to run 1.66 volts for stable performance even at low RAM clock speeds. QPI also needed to be nudged up to 1.3 volts.

One thing to remember as you fumble around the BIOS is that the uncore must run at twice the speed of the system RAM. Here’s where it gets a little confusing. The speed of the uncore is determined by multiplying the uncore multiplier by the base clock. On a Core i7-920 chip, for example, the uncore defaults to 16. The uncore thus is 16 times 133 for a total uncore speed of 2,133MHz or 2.1GHz.

To figure out the RAM speed, you have to take the memory multiplier and multiply it by the base clock. In the case of a Core i7-920 chip, the default memory multiplier is 8. So to determine the main memory speed, multiply 8 by 133 for 1,066MHz. Why aren’t higher DDR3 speeds available? The highest official memory speed of the Core i7 is DDR3/1066. You can overclock your RAM to higher speeds, but depending on the motherboard, the only way to accomplish a memory overclock will be to crank up the base clock for the CPU—unless you own an Extreme Edition CPU.

The take away here is to remember to keep the uncore speed at twice the speed the RAM runs. If you plan to run DDR3/1600, you’ll need to run the uncore at 3,200MHz. On a Core i7-965, you can run that speed without overclocking. On a Core i7-920, you’ll have to overclock the base clock to get the RAM at that speed.

More about QPI

Another new element to the Core i7 is the Quick Path Interconnect that we mentioned earlier. This high-speed interface connects the processor (or processors, in a multi-proc machine) to the chipset. Intel currently has two QPI speed iterations. The Core i7-965 Extreme Edition runs at 6.4 gigatransfers per second and the non-Extreme chips, such as the Core i7-920 and Core-i7-940, run at 4.8GT/s.

The QPI is important to watch because ramping it up too far can kill your overclock. For example, pushing the base clock from its stock 133MHz to 200MHz on a Core i7-920 means that the QPI will default to 7.2GT/s. That’s quite bit more speed than the stock 4.8GT/s; however, we successfully tested a Core i7-920 running at 7.2GT/s and believe that’s still within the realm of viability.

The QPI speed of the Core i7-920 and Core i7-940 is derived by multiplying the base clock (133) by 36, which equals 4788 or 4.8GT/s. The Core i7-965 uses a default QPI multiplier of 48, but unlike the non-Extreme chips, the 965’s multiplier is not locked. If you believe your overclock is failing because you’ve cranked the QPI too far, you can try dropping the speed by changing the QPI multiplier. On some overclocking runs with a Core i7-965 Extreme Edition, we had to drop the QPI back from 7.68GT/s to 7.04GT/s to increase reliability. The bad news is that you can’t do this with the budget chips.

Turning off the CPU VR Current Limit Override in the BIOS prevents the CPU from throttling back the multipliers under the Turbo Mode. Notice the lack of Turbo Mode tuning versus that with an Extreme Edition installed.

Va Va Voltage

You probably learned as a three-year-old not to mess with electricity after that incident with the wall socket. The dangers of electricity haven’t changed, but to wring the greatest clock speed out of your CPU, you’re going to need to overvolt the suckah. Actually, it won’t be just the CPU—our highest reliable overclock was only achieved by upping voltage to the CPU and parts of the chipset.

How much is too much? The default core voltage of the three current Core i7’s is 1.2 volts. We were able to push voltage to 1.5 on a budget Core i7-920 and successfully make it through some torture testing, but in our opinion, that’s probably too much juice (at least with air cooling). Sure, it ran our stress tests for a reasonable amount of time, but we don’t think the chip will live for long. A more reasonable voltage is probably 1.4 volts (just slightly more than the maximum allowable of 1.375), but take that with a grain of salt, too. Because your CPU, motherboard, cooling, and PSU will be different, the amount of voltage you can add will likely vary from our scenario.

Another area you’ll have to overvolt is the QPI interface. You’ll likely have to increase the voltage from its stock 1.1 to 1.3 to get a reliable overclock. Some folks recommend running QPI voltage at or above the CPU’s core voltage, but we didn’t have to on our budget chip as it was happy with 1.3 volts. Our Extreme Edition, however, needed 1.5 volts to the QPI, which was equal to the CPU voltage. Finally, you’ll have to add voltage to your RAM to get it to higher speeds. There has been chatter that a RAM voltage exceeding 1.65 can destroy a CPU— fortunately, most of the high-performance DDR3 binned for Core i7 doesn’t seem to need more than 1.66 volts to run, which is certainly within reasonably safe limits.

Sometimes the highest clock isn’t the best for performance with Core i7. Using Turbo Mode, we saw a 3.66GHz chip perform as well as one running at 3.80GHz, and without the excess heat and voltage.

Cool Running

Overclocking and cooling go hand in hand. If you can keep the CPU cool, you’ll increase your overclocking limit. For the majority of our testing, we used a beefy ThermalRight 120. As good a reputation as this cooler has, it’s still just an air cooler. Water cooling is an even better choice for overclocking as it’s more efficient at removing heat from the core. Better still would be an exotic phase-change or Peltier unit that could bring the CPU temps far below zero degrees Celsius.

What’s a safe temperature for Core i7? That’s also open to debate. We had to dig around the Internet to find that all three Core i7s have a maximum recommended temp of 67.9 Celsius. That, however, is the maximum temperature taken on the outside of the heat spreader with a calibrated thermistor. In English, that means that if you’re being told that all four cores are running 82 C under full load, you’re probably OK for the short term—but your chip probably won’t last five years. It would be wise to aim for 80 C or lower, and even better to run in the 70 C range. Just remember that you may have to crank it all back in the summer.

Breaking It Down

If your head isn’t spinning by now, you’re in good shape, but most people, even somewhat seasoned overclockers, will want a stiff drink after trying to absorb this information. So let’s review.

You buy a new 2.66GHz Core i7-920—you just couldn’t splurge on the Core i7-965 Extreme Edition. You’ve got a reasonably chunky air cooler, a good-quality PSU, and you want to overclock that proc. What should you do? First, you need to start goosing up the base clock until you get a clock speed that seems reasonable for the CPU. So, let’s say you want to aim for a nice conservative 3.5GHz. Start by setting your base clock to a speed that will get your CPU in the region. Take it from 133MHz to, say, 160MHz. The target clock speed you’ll want is actually 175MHz for 3.5GHz, but we’ll start with 160MHz.

We’ve read posts on the Internet of some people being able to reach a high clock speed without the need for additional voltage to the CPU, so you’ll want to see if your CPU is capable of it. If you want a good real-world test, run your favorite multithreaded encoder, such as HandBrake. Nero’s Recode is also multithreaded and will put a reasonable load on the CPU. If you want to really torture it, download Prime95 from www.mersenne.org. Unzip it and run Prime95.exe. Select In-place FFTs and make sure the number of threads is set to eight. By default, it should be eight for a Core i7. If it runs for, say, half an hour, you can aim higher. Add 5MHz to your overclock and try again. Go until it fails.

Extreme Edition CPUs feature unlocked QPI and memory ratios and even let you override the individual Turbo Mode settings and change how the CPU throttles under power loads to either let you run higher overclocks or nuke your CPU faster.

Now it’s time to add voltage. A good starting point is 1.35 or 1.375 volts. Since 1.375 is the maximum allowable voltage under spec, you’re actually still playing it very safe. While you’re there, you may want to add voltage to the QPI. So nudge it up from 1.1 volts to 1.3 volts. Some say that the QPI voltage should at least equal the core voltage, but that’s up to you. You should also add voltage to the RAM to get it to spec. If you’re using RAM rated for higher speeds, give the RAM the amount the maker suggests. The safe limit seems to be 1.66 volts.

Intel says it locked the QPI and memory multipliers on its budget chips but some motherboards appear to circumvent this. If your board does this or you’re running an Extreme Edition, which has unlocked QPI and memory multipliers, you can try backing down your uncore and RAM multiplier. Most BIOSes should correct the ratios for you, but remember that the uncore multiplier should be twice that of the RAM. So if the RAM multiplier is set to 10, set the uncore multiplier to 20. If you back the RAM multiplier down to six, you can set your uncore multiplier to 12.

Now reboot and rerun your stress tests. Keep repeating the steps we’ve outlined until you hit your target or hit a wall. Once you’re at your target, do a longer stress test with Prime95 to see if it is truly stable. You may have to add cooling or voltage to get it to run for several hours.

Remember, cooling and quality power matter. If you think you can do all this with a cheap power supply and straw heatsink, think again. Want to know how far can you get Intel’s cheapest Core i7 to overclock with air cooling? Read our case study to find out.

Case Study: Core i7-920

Can you make Intel’s cheapest i7 outperform the vaunted Core i7-965 Extreme Edition?

For our case study, we decided to stick with what the overwhelming majority of overclockers will select: Intel’s cheapo $285 2.66GHz Core i7-920. We paired this chip with an Intel DX58SO “Smackover” board, 6GB of Corsair Dominator DDR3/1600 RAM, an EVGA GTX 280 videocard, a WD 150GB Raptor, and a PC Power and Cooling Turbo-Cool 1200.

For cooling, we used a ThermalRight 120 and ran the board on a lab bench with three small fans for auxiliary cooling: an 8cm on the hard drive, an 8cm USB fan blowing on the RAM, and a 12cm fan directed at the voltage regulators and the heatsink.

We used Windows Vista Home Premium in 64-bit and ran a few benchmarks at the CPU’s stock 2.66GHz clock speed with the default Turbo Mode on. We then used the board’s OS-based overclocking tool for the majority of our overclocking attempts. Why? Normally we prefer the BIOS as we don’t want to deal with yet another app starting in Windows, but the Intel Desktop Control Center let us turn knobs and tweak settings without having to boot into the BIOS. This saved us invaluable time.

For stress-testing, we used a custom blend of Prime95 that Velocity Micro developed for overclock testing. We’ve long used the utility and have found it to push machines harder than any other test.

We know from previous experience that the Core i7 seems to need a minimum QPI voltage of 1.3 volts, so that’s where we started. We intentionally kept our RAM clock speeds down since we just wanted to see how far we could push the CPU, but we were surprised that we had to move the voltage to 1.66 volts to reach stability. After a day of testing and one OS reinstall, we decided that the best performance we could squeeze out of the Core i7-920 was 3.66GHz with Turbo Mode on. This was done with a base clock of 183MHz, the core voltage at 1.4 volts, the RAM at 1.66 volts, and the QPI at 1.3 volts for a QPI speed of 6.59GT/s.

With Turbo Mode, the default 20 multiplier occasionally reached 21 or 22 for an effective clock of 3.83GHz to 4.03GHz, which allowed us to achieve benchmark results on par with our higher overclock attempt: We topped our chip out at 3.8GHz with 1.5 volts but the CPU’s thermals were unacceptable, running into the mid 80s C. In our Lab in the winter, that’s fine, but we knew this overclock would never survive a real summer in a real home.

Our take away is that it should be very easy to push the 2.66GHz Core i7-920 by 1GHz, and more conservative overclocks of 3.5GHz or 3.4GHz should be extremely easy. But to expect a truly reliable overclock over 3.6GHz will require good-quality water cooling.

Core i7-920 Benchmarks

	2.66GHz (Turbo On)	3.66GHz (Turbo On)	3.66GHz (Turbo Off)	3.8GHz (Turbo Off)
Cinebench 64-bit 10 w/ 8-threads	16,097	21,474	21,013	21,640
Cinebench 64-bit 10 w/ thread	3,869	5,251	4,973	5204
ProShow Producer	11:43	8:05	9:40	8:45
3DMark Vantage Overall	14,720	15,010	14,963	14,984
3DMark Vantage GPU	12,099	12,133	12,133	12,129
3DMark Vantage CPU	42,042	51,987	49,860	51,012
Valve Particle Simulation	140	190	180	186
Main Concept Reference AVC Pro	11:57	9:13	9:16	8:57

Best scores are bolded.

How Reliable is Your Overclock?

If you’re ever in an online game where some dude brags that he’s running his blah, blah rig at blah, blah speed using special blah, blah tricks, take it with a pound of salt. Like the great fish that got away, people tend to inflate their overclocking achievements.

We were very happy with Intel’s Desktop Control Center as an OS-based overclocking tool but this 4GHz overclock was just wishful thinking.

Sometimes they don’t even know they’re exaggerating. If you think pushing a machine to 5GHz and running a game marks an overclocked rig as bullet proof, think again. The majority of today’s games barely push two threads, and even when they do, the CPU doesn’t do much. The truth is that much of the heavy lifting in games is done on the GPU, so you can’t use gaming as a true judge of a stable overclock.

Instead, try a multi-hour encode or transcode of a video using a multithreaded encoder like HandBrake. Even better, try a serious ball-buster like Prime95. This math-heavy prime-number hunter features a built-in torture test that is truly torturous. For the majority of our tests here, we used a custom-blend of Prime95 that we’ve found to put the heaviest load on overclocked CPUs. In our experience, the benchmark manages to properly put our overclocking hopes in their place by blue screening an unstable machine in mere minutes.

If your machine will withstand a couple of hours of Prime95, you’re doing good. If it’ll run over night, it’s bullet resistant. If it’ll run overnight in the middle of the summer, in an 80 degree room, well, you really have something to brag about.

Core i7 Budget Buyers, Beware

It got to be so easy to overclock Intel’s Core 2 line that a Mac user could one-mouse button the cheapest 10MHz Core 2 chip to 12GHz. That pretty much killed demand for Intel’s 3.2GHz Core 2 Extreme QX9770 CPU since the only difference was an unlocked multiplier and higher front-side bus (Intel’s insane pricing didn’t help, either.)

With the Core i7, Intel is being a far more aggressive in differentiating the Extreme chip. No longer is it just a multiplier lock. With the Core i7-920 and Core i7-940, you cannot set the individual Turbo Mode ratios. The thermal override switch and amperage override are also disabled. Finally, QPI ratios and memory ratios are similarly limited.

Does this make the Extreme Edition a chip that you must have? It depends. Swapping the Core i7-920 with a Core i7-965 Extreme Edition is like moving from a budget car to a luxury car built on the same platform. You’ll reach for a knob in the budget car that was there in the luxury car and find that it’s not there.

In our experience, it was easier to get the Core i7-965 to the limits imposed by our air cooling than it was with the budget CPU. While it took us an afternoon to get the Core i7-920 to a reliable 3.80GHz, we had the Core i7-965 Extreme Edition at 3.83GHz in a few minutes. By adding the Turbo Mode, we had the latter chip effectively running at 4GHz, and we’re certain higher speeds were attainable with better cooling. One thing to keep in mind though: While the Core i7-965 will likely reach higher speeds than the Core i7-920, it won’t give you the same amount of headroom. That is, you can get a 1GHz overclock with the Core i7-920 on air but you won’t be able to do the same with the Core i7-965 without water or something more exotic.

Is the 965 Extreme Edition a better overclocker? Certainly. Is it worth the extra $700? That’s a tough call and ultimately something only you and your bank account can answer.