HANDS ON GUIDE

Extreme Overclocking

Changing the FSB and vcore are only the first steps when it comes to overclocking. We spoke to two seasoned overclockers, both members of the Extreme Prometeia UK (EPUK) forums, to get some tips about tweaking a PC for maximum performance, as well as how to get started with sub-zero cooling.

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Number 1: The BIOS isn't the be all and end all

‘I’ll start [in the BIOS] with the CPU and try to max that out. Then I’ll move on to the memory and do the same,’ explains Peter Langworthy, aka Mr Dizzy, who is currently number one on the CPC benchmarks leaderboard (www.custompc.co.uk/benchmarks), and the only person to have broken the 2,000 points barrier. ‘After that, I’ll tweak the system in the OS. You can always get a little more out of it in Windows with ClockGen. I had a Core 2 Duo E6700 that would reach around 3.8GHz in the BIOS, but in Windows, you could push it to 4.4GHz.’

Number 2: High overclocks need the cold

‘If you can’t keep it cool enough then it won’t work. The colder the system, the more volts you can push through and the faster it will run,’ explains Peter. ‘[This is why] phase-change cooling is still the best. You achieve a more stable overclock at a much lower voltage. I have a Core 2 Duo E6850 that’s reached 4.1GHz when water-cooled, but under phase-change cooling it will increase to over 4.5GHz.’ Kenny Clapham, aka 404, another stalwart of the EPUK forums agrees: ‘I use two water loops for cooling – one for the CPU and one for the GPU. I’m a big believer in keeping heat loads separate, so you can really see what each individual component is capable of.’

Number 3: Be very careful with sub-zero cooling

Water cooling can’t hit sub-zero temperatures, so you’ll need to use a phase-change cooler such as the Prometeia Mach II or liquid nitrogen (commonly referred to as LN2). Take care exploring this territory though.

‘I started off with air, then moved on to water and am now using phase-change cooling,’ explains Peter. ‘If you jump in at the deep end, you can end up with a very expensive pile of broken components very quickly.’

Kenny is similarly cautious. ‘The second you drop below ambient [temperature], a lot more can go wrong. Condensation won’t spare you for being a nice person, or because you tried hard to get it right,’ he cautions. ‘Screw up while using LN2, and it can be very serious. For your first exposure to it, I’d suggest being in the company of someone who’s used it before, even if it was for a purpose not computer-related.’ He advises starting with cheap kit when you’re learning about extreme cooling methods. ‘It isn’t really possible to have a dummy run or to get a feel for sub-zero without being sub-zero, so it can be fairly nerve-wracking the first few times. Learn to walk before you can run. If your first sub-ambient experiment is with a £200 motherboard and a £700 CPU, you deserve zero sympathy if you break it.’

Number 4: Know your hardware

‘Why waste money beefing up the cooling on a poorly clocked CPU?’ asks Kenny. ‘Cut your losses and buy another – a second-hand chip with proof of performance, or a chip with a known good stepping. It can save a lot of time and hassle.’

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