Re: GA-EP45-UD3L + Q9550 Vcore
While VID isn't a sure fire way to tell if you have a good chip, I'd put money on a CPU with a VID of 1.2V clocking on lower volts than one with a VID of 1.3V.
Look at the proof you have in front of you Chike. You may have seen people with a higher VID chip run higher overclocks with lower temps, but you won't see many E7200's with a VID of 1.062V, or that are able to do 3.4GHz on a mere 1.12V. For instance, my CPU needs 1.3V to do 3.4GHz, and an incremental rise there after to get to 3.8GHz. It then needs a disproportional boost in Vcore for another 100MHz gain.
VID's are completely individual for each CPU. They are tested and set individually. Intel set a VID for the purpose of auto to set a voltage that will definitely work at stock speed. It does, no doubt, contain a margin of safety. The margin of safety doesn't directly include Vdroop, as that would be an integral part of any CPU test. Intel would use equipment that droops under load because it's in the design specs. The resulting VID would then be set to the voltage the CPU needed - any droop and + a little extra to be sure and to counter higher amounts of droop on individual boards.
If we all trusted Intel to know what they were doing, we wouldn't be running CPU's out of spec. We'd all look at the rated speed and just "trust" them.
Your chip, if the VID is indeed 1.28750V, would be set to that in any compatible socket 775 board, P35, P45, X38, X48 or any of the older 9xx series boards too. To confirm your VID, run CoreTemp. It will show the CPU's hard coded VID value on the main screen.
There's not much benefit to trying for the least amount of volts at stock unless cooling is an issue, or you want to run the CPU in a HTPC, in which case you probably wouldn't choose a quad anyway. If you want to play, I'd be trying to find my max overclock using the standard VID (set manually in the BIOS, no settings on auto OR normal) and work from there.
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