Extreme overclocking

Posted at: Tuesday 28th February 2006 by Ben Hardwidge

They destroy expensive components for fun, they dabble with liquid nitrogen and they even mod beer coolers into PC cooling systems. Ben Hardwidge speaks to the extreme overclockers

However, in extreme overclocking circles, phase-change cooling is often now considered to be passé. 'I see "extreme" as meaning specialised liquid nitrogen, dry ice and multi-compressor phase-change cooling systems,' explains Andrew. 'These are products that you can't just walk into a shop and buy. Phase-change cooling is more mainstream than ever now. It's as easy to set up as water cooling, and it allows the enthusiast to get closer to the stars than ever before. If they're lucky, they might just beat a few of them too.'

Grin and beer it

The only problem with these ready-made phase-change kits, though, is that they cost the same as three respectable water-cooling kits, but more adventurous overclockers have achieved some great results for significantly less money. One of the most impressive is Barry's beer cooler mod.

'I got a beer cooler thrown out of a pub for nothing,' he explains. 'It has six outlets, so it could cool six different pumps if it was in a pub. Inside, there's a big tank that's normally full of cold water, and this cools an insert where the beer runs inside stainless steel pipes. However, I replaced the coolant with antifreeze, so I can lower the temperature to -24˚C. Most water-cooling rigs run at room temperature, but I can run a water-cooling rig at -20˚C.'

Barry's next step was to build a workbench to house it, which is an awesome sight to behold. 'It has an air conditioner built into it so the air circulates within the top chamber, which acts as the computer case,' he explains. 'It sends cold air in the top and then sucks it back into the unit in a closed loop, so that the air is always the same. Condensation is the biggest problem with extreme cooling, and this resolves it completely. It took me three months to build.'

Another way to get your temperatures even lower is to build a cascade system, where you connect the compressors of two or more phase-change coolers together in serial, where one compressor cools another one's gas. Overclockers at the top of benchmark leaderboards often use cascade coolers, but they're much rarer than your usual phase-change cooler. This is because putting one together is a royal hassle.

As Andrew says, 'I want to be able to use my machine 24/7, and cascades are for out-and-out benchmarkers who want to be the best at all costs. Cascades consume a horrific amount of power too. However, I enjoy competing with the cascade guys; some of the overclocks they can achieve are awe-inspiring (3.9GHz from an FX-57 is not uncommon in a cascade-cooled system). Cascade users command respect.'

Liquid nitrogen

After that, perhaps the ultimate way to get your processor's temperature down is to use liquid nitrogen - the stuff that almost put an end to the T-1000 terminator at the end of Terminator 2. Using a liquid nitrogen cooler is often the wet dream of extreme overclockers.

I ask Andrew if he's ever tried liquid nitrogen, and he replies, 'No, I'd probably freeze my hand and smash it like the scene in Demolition Man! But I'm in the top ten on loads of Futuremark leaderboards, which is really good for me, as most of the people I'm competing with use liquid nitrogen, specialist multi-compressor phase-change coolers or dry ice.'