Re: What voltage to use?
for 2.8 should be about 1.32 to 1.4 vcore but you shouldn't need to go over 1.47 for an OC under 3.5ghz
Apply a 40mm fan to your northbridge heatsink plugged into a controllable motherboard header or fan controller
once you have the cooling you can set your nb voltage to 1.4 (but check around first)
Start at 2.5ghz with 1.32 vcore and go from there raising the fsb till you don't boot into windows at which time you raise vcore by a notch.
Nothing should be set to manual, find the right setting for everything.
2500K 4.7ghz,P8P67Pro,120gb Force3, 8gb Vengeance,R9290,TX850v2,W7HP,LaCie Blue 22" crt COMMODORE 64 Silver Label 1Mhz/128D 4Mhz(Z80)