Overclocking: 25% To 4.00 GHz
Raising the multiplier even further to 10x increases the processor's clock speed from 3.60 GHz to 4.00 GHz. Here, the stock voltage of 1.250 V proved insufficient. The QX9775 CPUs were only able to complete the torture test with Prime95 after we increased their core voltage to 1.400 V.
We do not recommend running the processors for extended periods of time with the voltage increased by 0.150 V. These CPUs were manufactured on a 45- nm production process and the risk of electron migration is simply too high. Nonetheless, the overclocking potential is a little higher than that of the socket 775 QX9770.
At 1.400 Volts, both CPUs completed the Prime95 torture test without incident.
The next multiplier would be 11x, which forces the CPU to run at 4.40 GHz due to the 400 MHz FSB. The Skulltrail board refused to so much as post at this setting. Obviously, the frequency jumps are far too big if we rely only on the CPU multiplier. So the only other way to increase the CPU's clock speed further is to underclock the FSB. We attempted to boot the system with the settings 11 x 386 MHz = 4.25 GHz. Sadly, even with more voltage tweaking, we were unable to convince the review CPU's to boot at this speed.
|2x Core 2 Extreme QX9775 @4.00 GHz|
|CPU Frequency||4.00 GHz (+25%)|
|FSB||400 MHz (1600QDR)|
|Core Voltage||1.400 V|
|Memory Frequency||FB-667 (333 MHz DDR)|