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Ask the Doctor: Stock Cooler Safety

The Maximum PC Staff — Mon, 10 Nov 2008 18:45:44 -0600

How far can I safely overclock a CPU if I’m using a stock cooler? I was building a budget rig and when I had money left over, I decided to upgrade from a high-end Athlon 64 to a really low-end 2.2GHz Phenom. I want to up the performance, even by a tiny bit, but I’m hesitant to do it with a stock cooler. Please help!

—Andy Shores

There’s no clear-cut way to determine how much performance you’ll be able to squeeze out of your processor. It depends on a number of factors, including your motherboard’s ability to overclock, the reliability of your power supply, and the prowess of your cooler.

The Doctor has found that AMD CPUs tend to be more difficult to overclock than Intel CPUs in terms of how far you can push the processor’s speed. That said, you’re not going to destroy your machine simply because you’re using a stock cooler—not as long as you follow a conservative approach to your overclocking: Start by slowly cranking down your HyperTransport speed and ratching up your CPU frequency.

After each modification, you’ll want to test the stability of your machine. At first, just reset your computer and see if it boots into Windows. As you up the CPU frequency higher and higher, you’ll eventually hit a point where your computer will cease functioning. Note this value, reset your motherboard’s CMOS, and dial the CPU frequency to a few steps below the terminal point. Boot into your operating system and launch Prime95 (www.mersenne.org), our stress-testing application of choice. Run an instance of the app’s torture test for every CPU core you have—if your rig survives, you’ve reached a steady overclock.

SUBMIT YOUR QUESTION Are flames shooting out of the back of your rig? First, grab a fire extinguisher and douse the flames. Once the pyrotechnic display has fizzled, email the doctor at doctor@maximumpc.com for advice on how to solve your technological woes.

AMD’s new X4 quad core

Gordon Mah Ung — Wed, 26 Mar 2008 23:02:28 -0500

It’s been a pretty lousy six months in AMD fan boy land. Even the most vocal of fan boys have found themselves ducking for cover as AMD was hit with delays, production problems and errata bugs.

With the release of the Phenom X4 9850, AMD hopes to finally put some of those problems behind it. Dubbed “B3” chips, the new CPU no longer features the infamous TLB bug that hobbled performance of the original Phenom chips. If it isn’t already obvious to you, AMD is also reverting back to the X4 nomenclature that it had toyed around with before Phenom launched. New Phenom’s will now carry the X4 designation for quad cores and X3 for tri-cores (of if you want to be snide, quad cores with one bad core).

We tested the new 2.5GHz Phenom X4 9850 using an Asus M3A32-MVP board with 2GB of Corsair Dominator RAM at 1066MHz data rates, a 150GB WD Raptor, Windows XP SP2, and the new Nvidia GeForce 9800GX2 GPU. For a comparison, we populated a new 45nm Penryn Core 2 Quad Q9300 and a Core 2 Quad Q6600 in an EVGA nForce 790i Ultra motherboard. For those who don’t know, the Q9300 doesn’t have the same relationship that the Q6600 has to the top-end procs. Intel has cut the cache in half from the 12MB in a Core 2 Extreme QX9650 to 6MB in the Q9300. This makes it sort of a “Penryn-lite” chip. Why? There’s probably two explanations: Intel has either decided to do something with its Penryn CPUs with some bad cache (ala AMD) or it has decided to hobble the chip intentionally to give its top quad cores more of an edge. We set the pair of 1GB Crucial DDR3 modules at 1333 and installed Windows XP SP2 on a WD Raptor 150GB drive. Finally, the same reference GeForce 9800GX2 card was used in the same machine and the same public drivers were used for both tests. Is it fair to pit a DDR3 platform against a DDR2 platform? We think so. Afterall, we would have tested Phenom on DDR3 but there’s just no support for it yet. Even though the DIMMs in our Core 2 platform cost more than the CPUs, we think it would be unfair to not put the Core 2’s best foot forward. If anything, Intel is probably grumbling that the test should be conducted on X48 which, we’re sure, the company thinks is a better and faster platform.

For the most part, the Q9300 owned the night. It generally outpaced the old Q6600 quad core and the new Phenom quad core in most of our tests. In a clock-for-clock test between the Phenom and Penryn, we would declare the Q9300.

AMD fans shouldn’t hand their heads in shame though. The Phenom numbers weren’t so far behind as to be dead in the water. Certainly, it doesn’t go quite head-to-head with the Penryn-lite but it is still fastest AM2 chip available today for most apps. That makes it a pretty good upgrade for those with AM2 boards that are capable of supporting Phenom. If you had to start afresh though and you weren’t opposed to Intel for anything other than religious reasons, Core 2 is still the champ in the cheap quad core category.

AMD’s big problem is expectations. When Phenom first launched late last year, the company had built up wild expectations that Phenom would level the playing field with Intel’s quad core. In truth, all it could do was barely compete with Intel’s lowest of the low quad cores – a chip that was a year old. AMD still has no response to Intel’s 3GHz Core 2 Quad QX9650 and the soon to be released 3.2 Core 2 Quad QX9770 chip and it doesn’t look like the company will for several more months. Meanwhile, Intel is already demonstrating fully functional Nehalem CPUs and says they’re on track to launch later this year.

Benchmarks
	Core 2 Q9300	Core 2 Q6600	Phenom X4 9850
Clock	2.5GHz	2.4GHz	2.5GHz
L2	6MB	8MB	2MB
L3	N/A	N/A	2MB
Rated TDP	95 watts	95 watts	125 watts
FSB	1,333	1,066	N/A
Bulk Pricing	$266	$266	$235

3DMark06 Overall	13,990	13,565	13,594
3DMark06 CPU	4,103	3,856	3,807
Valve Particle Test	87	76	72
Valve Map Build (min:sec)	2:42	2:48	2:57
CineBench R10	9,622	8,763	8,065
ScienceMark 2.0	1,572.21	1,393.57	1,606.46

PCMark05 Overall	9,080	8,948	8,547
PCMark05 CPU	8,064	7,746	7,396
PCMark05 RAM	6,012	5,434	4,761
PCMark05 GPU	15,643	15,806	13,972
PCMark05 HDD	7,633	7,647	7,766

Adobe Premiere Pro CS3 (min:sec)	15:45	17:33	18:01
Photoshop CS3 (min:sec)	2:20	2:28	3:35

FEAR (fps)	199	209	200
Quake 4 (fps)	169.7	166.6	165.7
Unreal Tournament 3 (fps)	119	105	87
AutoGK DIVX 6.8 (min/sec)	9:36	10:07	11:44
AutoGK XVID	11:08	11:38	12:42

It's A War Of Words Between Intel and AMD

Gordon Mah Ung — Wed, 19 Sep 2007 16:33:19 -0500

Intel's Pat Gelsinger with the company's upcoming dual Core 2 Extreme "Skull Trail" system.

The CPUs aren’t even out yet but the war of words has already begun between Intel and AMD over whose CPU is bigger, err, better. While Intel showed off early samples of its next-gen Nehalem CPU at its annual developer conference this week, AMD was sniping at the company from the sidelines.

The big splash came from Intel which said that it would have its 45nm-based Penryn family of CPUs out this fall, the company also demonstrated its, next next-generation chip, code-named Nehalem, up and running a year before it's even scheduled to be launched.

Nehalem will be scalable from 1 to 8 cores and will bring back a form of Hyper-Threading, but the big change from previous Intel processors will be the inclusion of an integrated memory controller. The three-channel DDR3 controller will work along with a new chip-to-chip communication protocol dubbed QuickPath. Previous generations of quad-core chips, including the new Penryn processor, continue to use a shared front-side bus toplogy. For one core to communicate with another core on another die, it must use the much slower front side bus. Intel has addressed by increasing the bus to 1,600MHz for its server and workstation Penryns, but Nehalem will have a much faster connection between CPUs at it's beck and call.

That got AMD into the spin game by whispering to anyone that would listen, that they were right!

“What's amazing is that many of (Intel’s) ‘groundbreaking, innovative new technologies’ are close facsimiles of technologies AMD pioneered, is already shipping, and in some cases, has been shipping for years,” AMD crowed to the media. “For example, products that are more than a year away, like Nehalem (compare to native Quad-Core AMD Opteron), and QuickPath (compare to AMD Direct Connect Architecture and HyperTransport) are simply Intel's admission that AMD was right all along about an integrated memory controller being the key to a superior processor architecture.”

AMD first moved the memory controller from the chipset directly into the CPU die with the Opteron and Athlon 64. The chips also utilized a chip-to-chip communication protocol based on HyperTransport instead of a front-side bus topology. CPUs weren’t the only thing AMD pooh-poohed. The company also said Intel’s graphics project, code-named Larrabee (which Intel publicly confirmed this week) sounded pretty damned similar to its own Fusion project that will combine ATI graphics with AMD CPUs.

Obviously sensitive to AMD’s jibes, Intel exec Pat Gelsinger, acknowledged the similarities.

“When you look at that simple system architecture they look pretty similar,” Gelsinger responded rather testily to a media question. “On a gross level they’re very similar.”

But Intel's Gelsinger shot back, if Opteron’s on-die memory controller and chip-to-chip is so bad-ass, why does a Harptertown (Intel’s Penryn-based Xeon) using the outdated front-side bus already outperform Barcelona? Gelsinger attributed it to Intel’s superior cache design and the bus. “When we bring those big caches over to Nehalem, that superior cache architecture, wow.”

"(With Nehalem) we’re going to have a superior systems architecture, dramatically superior system bandwidth with superior caching technology,” Gelsinger booasted. “The instruction per clock of Merom is still ahead (of Opteron), and Nehalm jumps those even further. “So (Nehalem has) a superior microarchitecture, cache technology, and memory bandwidth -- This is a phenomenal platform.”

Translation: We’re going to kick AMD's ass. Gelsinger’s and AMD’s posturing aside, all bets are on Intel for this season. Penryn will make its debut on the desktop and server within the next two months while AMD’s first Barcelona chips were shipped at a disappointing 2GHz. Meanwhile, AMD’s great green hope, Phenom FX, may not debut until December. Too late to make the crucial Christmas shopping season. There’s been speculation that AMD’s problem lies in fabrication problems--with low yields being a common explanation. Matters weren’t helped when the company announced that it would release a triple-core core Phenom in 2008. While some say AMD’s tri-core plans could work because it would fill a price and demand gap between dual-core and quad-core machines, it left an opening for Intel to pee on AMD’s parade.

Is AMD doing this to fill a non-existent gap, or is AMD having problems with its native-die approach that it’s trying to cover up? AMD has made much hay of its “true quad core approach,” which puts all four execution cores on a single contiguous piece of silicon. Intel, meanwhile, still builds its quad-cores by joining two dual-core dies inside the CPU package. While AMD’s architecture is more elegant, it also can lead to lower yields as each execution core on the die must be functioning for it to be made into a CPU. Intel’s yield could be drastically better since the company only has to two find matching dual cores to make a quad core. In other words, AMD must make its quad-leaf clovers by finding perfectly formed ones while Intel can construct them using two, two-leaf clovers. Intel’s pragmatic, but architecturally inferior approach could prove to be right in the end. Intel officials say yield issues aside, it's already selling $200 quad-cores, so why would anyone want a tri-core?

Enthusiasts confidence in AMD also took a hit when rumors surfaced on the Inquirer that AMD’s much touted FASN8 dual-processor uber-enthusiast platform may have fallen under executioners axe. The company rep couldn’t confirm or deny the rumor when Maximum PC asked.

Even if FASN8 is dead, Intel says it plans to roll forward with its V8 platform. Like AMD’s FASN8, V8 is a dual-processor board offering up to 8 execution cores in a single PC. But unlike its workstation brethren, V8 would offer up to four physical and electrical x16 slots and be based on an Intel platform dubbed, Skull Trail.

Numbers don’t lie (that much)

Gordon Mah Ung — Thu, 19 Apr 2007 18:49:10 -0500

Experts often tell us that the performance segment doesn’t really matter that much in the PC market. Sure, there is a minor halo effect, but people really don’t care if a Core 2 Duo is faster or if an Athlon 64 FX-55 is kicking ass – they buy on price.
With the general volume of CPUs being in the hundreds of millions, the impact of a quad-core or the original FX really has no impact they say.

Really? In an utterly unscientific, statistically incorrect test, I decided to take the CPU market share numbers provided by iSuppli today and overlay the launch dates for several CPU models. If the performance of the original Athlon 64 X2 4800+ really didn’t matter to the public, we shouldn’t see any impact right?

Take a look for yourself. While statistics can lie, be distorted or stretched to prove almost anything, these numbers seem to support my position that who makes the fastest CPU still matters.

The latests numbers seem to show that AMD made inroads based on the performance of the Athlon 64 and really set the world on fire with the X2's. When Intel and AMD swapped performance places with the Core 2 Duo, Intel suddenly started taking back market share.

Of course, it would be wrong of me to lay this chart out without mentioning that other forces might have an impact. When Intel pumped out the Core 2 Duo, it also went on a mad rush to jettison every NetBurst-based CPU for a song and a dance. At the same time though, AMD finally made it into Dell boxes and engaged in its own firesale to get its CPUs moving again so why would the company lose share?

What’s the right answer? Who knows, but just like the fascination with how well Barry Bonds performs at AT&T park against left-handed pitchers when hot dog sales are up on Tuesdays, it’s always fun to crunch the numbers and wonder. I for one believe that Intel and AMD are doing their best when they’re making fast CPUs. When either tries to cover the performance gap with pricing schemes or marketing guff, the little line tends to go down.