Ultimate BIOS Guide: Every Setting Decrypted and Explained!
Posted 06/15/09 at 12:35:52 PM by Paul Lilly
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.
Great Piece but...
Submitted by Mikeytron on Thu, 07/02/2009 - 10:44am
I second another poster. This needs to be in .pdf form. You did a whole lot of work but the value to us is limited because we really cannot easily "take it with us". Yeah we can bookmark it but that's really not good enough. To be honest what needs to be done is to create a smaller pocket sized book that we can keep in our desks or briefcases. This is an item that has value unlike the CD'S that come with the issues. In fact how about when we subscribe we get a pocket sized how to book on the above piece? The CD is good for people not online, but really we ALL are by now big time. Simple links in the mag every month could do away with the CD and you would be going green!!! Give us hard copies of stuff we want to KEEP, again like the above piece. The CD usefullness is DEAD.
Try this
Submitted by One4yu2c on Sun, 07/05/2009 - 9:37am
It's not PDF, but maybe this would help? http://www.maximumpc.com/print/6543
Could also combine the single-page print version with Firefox's PDFit extension.
-Paul Lilly
Enabling AHCI after Windows has been installed
Submitted by domih2009 on Wed, 06/17/2009 - 9:34pm
...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.
You can save yourself a new Windows installation depending on your OS and ICH chipset.
For Vista: http://support.microsoft.com/kb/922976 (easy)
For XP: brave minds can peruse through http://www.google.com/search?q=How+to+enable+AHCI+on+Intel+under+XP (less easy)
Great article! I doubt, that
Submitted by babalooo on Wed, 06/17/2009 - 1:20am
Great article! I doubt, that many people are aware, just how time consuming such work is. Respect...
If you are having pc gaming performance issues, you're welcome @ http://www.lowfps.com/improving-performance
Fantastic Guide.....BUT.......
Submitted by ghot on Tue, 06/16/2009 - 6:32am
......kind of useless if I cant down load it, since i seriously doubt that Ill be ONLINE while OCing in the BIOS :)
This DESERVES to be in .pdf format, as well as the linked to articles ^^ Remember also that nVidia still makes chipsets :)
Take an OS, and edit out all the efficiency, and what you have left is a post-XP Microsoft operating system :)
simply copy paste it to
Submitted by Bless on Wed, 06/17/2009 - 3:17am
simply copy paste it to word, and hit print
Sweet
Submitted by FenixSS on Mon, 06/15/2009 - 11:22pm
Another example of great bathroom reading material.
Great job Paul. This is
Submitted by rob41 on Mon, 06/15/2009 - 6:29pm
Great job Paul. This is some very useful information!
Awesome!
Submitted by water_man3 on Mon, 06/15/2009 - 12:10pm
One of my favorite issues of all time, the August 2003 issue, happens to have - I quote - "the most in depth white paper - EVER" on BIOS Secrets. This is great stuff guys - exactly why I subscribe.
Limit CPUID Max. to 3, page 2
Submitted by Dysthymia on Mon, 06/15/2009 - 11:34am
I'm confused... the only users who should have this setting enabled are those running a legacy os with an older processor -- and those running XP, Vista, or Windows 7?
I saw the same thing. This
Submitted by BlazePC on Mon, 06/15/2009 - 7:20pm
I saw the same thing. This article, although well intentioned, has some really poor grammar/explanation of logic in relation to BIOS "settings". I'm actually quite shocked at how bad some of this reads. I subscribe to the mag and I'm coming up on renewal shortly, and this may have been the straw that changed my mind on doing that. Pretty sloppy guys...you might consider clearing up the explanations for the "new" user base on the next go around ...and there will be a next time because this stuff gets recycled a lot.
Great article
Submitted by Mothership on Mon, 06/15/2009 - 10:35am
I found this very helpful and already printed a copy for myself and others. Good if you want to learn what your ACTUALLY doing when your OCing that cpu =).
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