Is there any reason for a CPU to require a higher Vcore to achieve stability when running at a certain speed, than the Vcore that the same chip requires for stability when running at a higher speed?
Specifically, I am (moderately) overclocking my Ivy Bridge i7 3770K. I am not touching the BCLK, leaving that at the default of Auto (100.00 Mhz), turning just the multiplier.
When I have the multiplier set at x44, the system is perfectly stable (judged by stressing with Prime95 for a few hours), with the Vcore turned down to 1.200v.
If I dial the multiplier back down to x43, the system is no longer stable, and crashes after less than half an hour of Prime95. In order to be stable, I need to crank the Vcore back up to 1.220v.
(This happens regardless of what the VCCPLL is set to, this happened when it was on Auto (1.800v), manually set to 1.800v, and also when it was pushed down to 1.505v - so this seems irrelevant at this point).
Admittedly, this is not a huge difference, nor is it a very big deal - 1.220v is still agreeably low.
However, I am bothered because to the best of my knowledge,
higher frequency should require higher voltage.
Why would my chip need a higher Vcore at x43 than it does at x44?
(If it matters, my motherboard is a GA-Z77-D3H.)