CustomPC and BenchTec overclocked the Intel Core 2 Duo E8600 as far as it could go
We recently had the chance to test Intel's latest overclocking-friendly CPU, the Core 2 Duo E8600, at Amari's labs near Watford. Not content with merely wowing us with their Dream PCs 2008 entry - the fantastic submersion-cooled XCP - Amari provided the facilities to overclock the E8600 with liquid nitrogen. Custom PC was aided by two of the UK’s best-known overclockers from BenchTec, Sacha35 (Paul Watkinson) and Bazx (Barry Wynd), where we cooled the chip to a chilly -120°C and achieved some truly impressive clock speeds and benchmark results.
Liquid Nitrogen isn't easy to obtain in large quantities, but thanks to a contact provided from our work exchange student, we were able to obtain 25 litres of LN2, from a bio-research facility where it is used to freeze cell samples.
Testing was delayed for an hour or two due to some driver issues with Radeon HD4870X2, preventing us from running any meaningful 3DMark benchmarks. After we had solved this issue, we applied the LN2 and Paul and Barry were able to set to work in the BIOS, increasing both clock frequencies and voltages.
Rather than using Windows XP or Vista, we performed testing using Windows Server 2008. This operating system has lower overheads and a more stable design, making it much easier to work with at extreme clock frequencies. To squeeze every last point of benchmark performance from the hardware, we were able to disable all non-essential services in Windows before performing any tests. To eliminate the I/O bottleneck from any results, we used a Crucial SSD and two Gigabyte I-RAM drives in an 8GB RAID 0 array.
Leaving the multiplier at 10x, our liquid nitogen cooled system had no problems running with a clock frequency of 6GHz, by increasing the CPU voltage to 1.9v. The Asus Rampage Extreme motherboard didn’t even flinch at exceeding 600MHz FSB. At this speed, the E8600 managed an incredible SuperPI 1M rating of 7.8 seconds. A brilliant initial score.
After this, we spent time tinkering with many of the options in the BIOS then using the Rampage Extreme’s TweakIt overclocking controls to fine tune primary voltages and clock speeds without having to reboot.