P6T 3.8 to 4.2ghz - voltage difference.

[MittWaffle]

I have my system 100% stable at 3.8 @ 1.25v vcore however when I go to 21x200 or 20x200 I need to hammer the voltage to 1.375-1.4375 vcore to stabilize it. I have IOH, ICH and QPI voltages optimized aswell.

What is causing this huge voltage gap?
Even a 200 MHZ increase causes a need for 1.375vcore up from 1.25

[gingerbee]

the sweet spot for i7 c1/c0 920 and this is jmo

[bojangles]

That's just the way it is really. It's highly dependent on the chip. Some may not need as much, others will need a lot, like yours. My i7 920 D0 can run 4 GHz at 1.18V, but runs extremely hot. The transistors in your chip may need some extra voltage to stabilize currents.

[gouki]

Yeah i had the same thing with my D0 as well. I could reach 3.8ghz with stock volts except for ram which i put to 1.65 to rule out ram problems. Went from 1.25 to 1.3125 in bios to reach 4ghz and that's all i changed. I'm new to oc'ing the i7's so i don't know much about the other settings so i left them at default.

[bkh2]

I'm just curious. What do you have your IOH, ICH and QPI voltages set to? Also, are you running a C0 chip? What cooling do you have, and what are your temps?

I too, have the Asus P6T and am currently running a D0. I hit 4 ghz stable @ ~1.265V, but I'm trying to reduce voltage by optimizing the other voltages.