AMD Cranks Phenom II To Record 6.5GHz

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"There is no bottom for Phenom II that we've been able to find yet," said Simon Solotko, a senior manager in Sunnyvale, Calif.-based AMD's desktop division, explaining that overclockers using exotic cooling solutions haven't been able to locate the "cold bug" point on the Phenom II silicon -- a temperature so low that the processor stops working.

"We had done a lot of work to improve signal processes [on the Phenom II], and in our early testing we found that they exhibited no cold bug," Solotko told "Processors, in general, exhibit a cold bug, which means they won't operate below a certain temperature, so the [Intel] Core i7s, for example, won't perform below -100 degrees. With Phenom II, you can pour liquid nitrogen on and let it rip. There's no bottom near -190 degrees."

AMD had already generated a lot of ink ahead of the Phenom II's CES launch with a series of overclocking events like one in November at the company's Austin, Texas-based campus, where they overclocked one of the new 45-nanometer quad-core chips to 6.3GHz.

For those sessions, AMD relied on liquid nitrogen to chill the chips, but Solotko said the team was wondering how out of control things could get if they went even colder.

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The chip maker's desktop team includes noted Finnish hardware tweaker Sami Makinen, officially employed as a product manager, but known more generally as the Grand Poobah of Overclocking in Austin. Makinen, who is the key developer of AMD's Overdrive software interface for overclocking, teamed up with AMD engineer Pete Hardman and a crew of Finnish overclockers to put on the CES event.

Having taken Phenom II to the limit on liquid nitrogen, the team decided to go even colder with liquid helium -- a non-naturally occurring substance so cold that the normal linguistic reference points of ice, snow and shivering make no sense when talking about it. Liquid helium is so cold, in fact, that it's colder than the vacuum of space, Solotko explained.

So kids, not only should you not try to replicate AMD's CES results at home, you shouldn't try this at home even if your house is on an asteroid.

The upshot is that Makinen and Co. took a Phenom II X4 940 Black Edition part -- listed at 3.0GHz off-the-shelf -- to 6.5GHz, a world record for an x86 quad-core processor. AMD also set the score to beat the 3DMark05 benchmark, topping 45,000 for the first time ever with a mark of 45,474.

Pretty gaudy numbers to process if you weren't around to see the performance, so luckily there's video:

The upshot for AMD is that such extreme sessions yield solid data for its engineers, Solotko said. The PR buzz shouldn't hurt the financially struggling company, either. AMD's new Dragon desktop platform -- comprising the quad-core Phenom II, 790 series chipset and ATI Radeon HD 4800 series graphics -- is seen as a marked improvement over last year's Spider platform built around the first quad-cores from the chip maker.

Of course, in the real world nobody's building a practical liquid nitrogen-cooled system, let alone a liquid helium rig. We'd need to build a dozen more burn wards in every major city if they did. And Intel's Core i7 may not have the overclocking headroom at the extreme outer limits, but it still beats AMD's best on many of the performance-based benchmarks when overclocked on air alone.

That said, the three Core i7s available now burn through a lot more juice at idle than any Phenom II, and they're a lot pricier to boot. AMD's 3.0GHz X4 940 costs $225 after a recent price cut. The entry-level Core i7-920 (2.66GHz) is $284. Intel's new chips also require a complete (and expensive) system overhaul, whereas the Phenom II can drop into older rigs built around last year's first Phenom chips.

Even if you happen to be one of the many people who does not own a Phenom I system (judging by AMD's 2008 sales figures we should probably amend that to "the many, many who do not"), a new Dragon system would probably net you a $200 to $250 savings over a comparable Core i7 box.

And while nobody's commercially pushing Phenom II overclocked to 6.5GHz, that doesn't mean system builders aren't taking advantage of the headroom. Take Rain Recording, a maker of high-performance digital audio workstations, which has built a new Phenom II-based desktop called Element X that ships at an overclocked 4.1GHz.

Jacking up the off-the-shelf processor clock speeds that much in a system's default configuration isn't something his company ordinarily does, said Rain Recording president Bill Paschick.

"We did it because there's so much headroom in that CPU. It's really 'stabilized overclocking,' if you will -- we're not about overclocking normally," he said.