Last week AMD invited CrunchGear down to Austin to check out an overclocking event they were holding, at which many, many liters of liquid nitrogen and the much colder liquid helium would be consumed by thirsty processors. They asked us, however, not to video the entire event, since they’d have their official video coming out shortly and some of the technology being used was still in development. No problem, we said, we’ll just dip our pulled-pork tacos in the spare liquid nitrogen.
A lot of stuff actually went down there. I’ve always wanted to get up close and personal with some of the weird cooling solutions these overclockers use, as not only do they just look cool, but they result in performance numbers hugely ahead of anything possible with traditional methods. And it’s not like you can just buy these setups at the store; one of the overclockers in attendance, name of K|ngp|n, is actually an accomplished metalworker and manufactures the pots he uses himself. Pots being the containers which hold the coolant and pass the temperature difference on to the processor, you know. The thickness, material, and surface design of the pot is important to where and how fast it accepts or gives off heat.
I know you didn’t click through looking for a lecture on physics, but this stuff is crazy enough to warrant your attention. It seems that processors for the last few generations have had a sort of allergy to extremely low temperatures. At very low temperatures like those created by liquid nitrogen (LN2), silver and gold do just fine as conductors, and in fact their conductance is actually increased a little around that temperature (a little over -200°C, or -323°F) if I remember right. But beyond that temperature, their conductance drops like a rock.
Copper, however, is an excellent superconductor at even lower temperatures. In fact, liquid helium (LHe4) brings it just about to its maximum conductance temperature: around -250°C. That’s not too far from absolute zero; LHe4 boils at 4 kelvins, making it one of the coldest substances we have access to. And that’s what we were pouring all over the Phenom II. It turns out that the Phenom IIs thrive like no other under these insane conditions, and although it doesn’t make overclocking a cakewalk, it does make some things possible which weren’t before.
So enough with the science, what was going on there? Well, basically the overclockers set up their rigs, cooled them as much as possible, and hit the benchmarks until either the world record or the motherboard gave out. They were aiming for 7GHz and 50,000 in 3DMark05, which are ridiculous goals but totally doable when you’ve got 600 liters of LH4 at your back.
Some interesting things I noted: the overclockers insulated their motherboard with kneadable eraser, which is a great insulator and doesn’t stick to components. LHe4 is used up at a rate of almost a liter a minute, so K|ngp|n would cool his processor down as far as he could get it with LN2 before dropping in the far more expensive LHe4.
The pots they used were super-specialized; the LHe4 one has a special design for dealing with LHe4′s tendency to evaporate instantaneously on contact with anything, and the LN2-only pot was the first see-through one in the world. It’s got two walls of thick lexan with what is essentially everclear filling up the middle. The alcohol had the lowest freezing point of any clear liquid they tested, and I found out to my great surprise later that yes, it does get extreeeeemely cold when it’s buffering a boiling pot of LN2 for a few hours.
Unfortunately the guys didn’t hit their 7GHz and 50,000 goals, but did they get damn close. K|ngp|n posted his results over the weekend: 49,089 3DMarks and 6893MHz. Here was his setup and posted results:
- ASUS CROSSHAIR III and M4A79T-deluxe motherboards
- AMD Phenom II 955 ES LHe4 cooled
- CORSAIR DOMNATOR GT and 1800CL-7s
- AMD 4870X2′s in quad X-fire stock clocks & cooling
Next time, maybe. Thanks to AMD for inviting us out. Their official video, with more details on the overclockers themselves, will be coming out shortly and we’ll link it up then for the hardware enthusiast CrunchGear readers. There’s a more extensive gallery here if you want to drool over their setups more.