At stock settings, the Core 2 Extreme QX9775 runs at 3.20 GHz. While there is a multiplier option in the BIOS, it applies to both CPUs simultaneously, so that both processors are overclocked. Since choosing different multiplier settings for each of the CPUs is not possible, the success of your overclocking experiments will always depend on the "weakest" CPU. Statistically speaking, the chances of a good overclock are thus lower than for a single-socket system. By raising the multiplier from 8x to 9x, CPU frequency increases to 3.60 GHz.

We did not need to increase the CPU's core voltage to reach this speed. Both processors effortlessly achieved an overclock of 12.5% to 3.60 GHz at their default voltage of 1.250 V.

Stable at 3.60 GHz with default voltage

Our overclocking attempts were not always successful with the sample Skulltrail board and its beta BIOS. Sometimes it wouldn't start or would get caught in a POST loop. In some cases, we weren't even able to boot the system at default settings.