New P8P67/i5 2500K. Vcore Offset. WTF?

[di_entropy]

just got my new system up and running and been doing some stress testing/ocing

i am not sure what is going on with my vcore though

i thought i had it set to 1.350V under full load using the offset method by looking at Coretemp but after investigating a bit it seems this is not the case

this is manual 1.350V


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this looks pretty good, but i wanted to use the offset method so that it can scale down the vcore when cpu is not being used

so here is offset +0.020V


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offset +0.060V


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offset +0.120V


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offset -0.040V


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so i'm guessing i should be looking at asus AI suite and CPU-Z since they seem to be showing the same vcore values

offset +0.020V gives me 1.416v under load.. so you would think that for 1.350V you would set offset to -0.040V right?

wrong. that gives me 1.440V

what the hell is going on?

how exactly does offset work? what is the base value that it uses to offset?

originally i was just looking at the vcore reading in the bios, and thought that the offset just added to this value, but this is not the case.. the vcore reading in the bios seems to be a lower "idle state" value

confused

[di_entropy]

ok, it seems that load line calibration inadvertently boosts vcore

i dropped it from extreme to ultra high with an offset of +0.005 and it's sitting at around 1.368V under load now

[Bertross]

be careful you have your FSB at 103, it needs to be really 100. Make sure you look in the EFI about making the CPU cores not adjustable in OS.

when thats selected you will need to input the 4 core value multi, eg 46x100 = 4600mhz

Make sure you have latest CPU-Z.

My 2600k loads at 1.28volts at 4.6Ghz, phase power set to extreme, it evenly distributes power more precise for high clocks.

[defecat0r]

Originally Posted by Bertross

be careful you have your FSB at 103, it needs to be really 100.

can i ask why this is? danger of blowing something up?

From what i've been reading on this guide:
http://www.overclock.net/intel-mothe...ing-guide.html
there is no way to know exactly what voltage you're going to end up with when playing with the Offset voltage and the Additional Turbo Voltage, you just need to adjust it till you get what you're after in in windows.

I've got the -M version of your board, so i'm going to assume your board is pretty much the same.
This guide is saying put one or two steps into CPU Offset Voltage ( + 0.005 or a tad more) and then just leave that alone. That's just the idle voltage, mine seems to go as low as 0.992V on idle, i might try dropping it once i'm satisfied i've got a stable OC.
The ONLY voltage you should be adjusting then for your OC'ing is the Additional Turbo Voltage. Basically run it up bit by bit till you get what you're after in windows, but keep in mind that pushing u'r overclock further seems to push that voltage higher as well so just need to keep an eye on it.
Also, this is all with Load Line Calibration DISABLED. I haven't tried messing with my voltages to accomodate having it enabled yet, but from what i can see there really is no reason to use it at all.

This method has worked pretty good for me anyway, just to sum up,
Load Line Calibration DISABLED
CPU Offset voltage + a couple of steps,
Additional Turbo Voltage to alter the voltage when turbo mode is on, i think mine is around 0.13V

[di_entropy]

thanks for the info bertross

everything seems to be going good now

priming at 46x103 4740mhz at 1.36v under load.. temps reaching around 65c max

[Bertross]

asus reckon 107 is max on the bus. Thats why its recommended to leave at 100. have fun boys