CPU voltage question

[AD-15]

hello,

What determines the voltage that should be put across a CPU? Is it purely the clock speed? Or is does the multiplier/FSB setting play a role aswell? Ie, would a 500 FSB x5 (2.5GHz) require the same voltage as a 250FSB x10 (2.5GHz) configuration (numbers made up obv.)?

Thanks!

[Will404]

You select the voltage, (try and get the lowest stable volts)

[moogle]

hello,

What determines the voltage that should be put across a CPU? Is it purely the clock speed? Or is does the multiplier/FSB setting play a role aswell? Ie, would a 500 FSB x5 (2.5GHz) require the same voltage as a 250FSB x10 (2.5GHz) configuration (numbers made up obv.)?

Thanks!

Yes, for the vCore, but for VTT or VNB you might have to raise the voltages. VTT is the FSB voltage and running at high FSB's require more. Usually the CPU voltage doesn't have to be adjusted though. Remember if you're on a 45nm CPU don't go over 1.4VTT as it may kill the CPU.

[matty-hodgson]

Yes, for the vCore, but for VTT or VNB you might have to raise the voltages. VTT is the FSB voltage and running at high FSB's require more. Usually the CPU voltage doesn't have to be adjusted though. Remember if you're on a 45nm CPU don't go over 1.4VTT as it may kill the CPU.

so that's what the VTT voltage thing is?
do you need to raise that on a Q6600 to achieve higher overclocks?
what's the 'safety range' on a Q6600?

[moogle]

so that's what the VTT voltage thing is?
do you need to raise that on a Q6600 to achieve higher overclocks?
what's the 'safety range' on a Q6600?

1.55v is the max for 65nm according to intel datasheets. You will only need to raise that as you go into high FSBs, maybe past 450 ish or more. I need to raise mine when I go past 460 FSB. You can do simple tests to see if you need more VTT, at the FSB you need for your overclock set your multiplier to it's lowest in the bios and then boot and do some priming. If it fails even though the CPU is within a freq which is achievable at that vCore (make sure you keep the CPU voltage at what it was even if you are lowering the multi so that you don't introduce new problems when finding where needs more volts) then you know you need a bit more VTT.

[AD-15]

hello,

Thanks for the advice!

I've been doing some testing, and so far my overclocked 3.2 GHz E6600 (400FSB and x8) has been stable at stock voltages. If it remains stable with the rest of the tests I perform, does that mean I'm ok to leave it at the stock voltage, or should I increase it by one notch? If I don't supply the CPU with enough voltage, but it remains stable, could there be any damage?

Thanks again!

[moogle]

It won't get damaged if you don't supply it with more, it'll just be unstable. Remember don't leave voltages on auto when overclocking as the motherboard will automatically increase them.

[iranu]

Read this article http://www.anandtech.com/showdoc.aspx?i=3184&p=3 - it will tell you everything you need to know with regard to overclocking 45nm cpus, power, voltage, FSB, "vdroop" etc.