The way a it works is you up the speed until it is not stable. Then you up Vcore to a point until it is stable (within limits). These 45nm processors are rated up to 1.362 Vcore, unless you have adequate cooling in which case you get a bit more leeway. You are well within the safe zone @ 1.175. 3Ghz is an extremely mild overclock and you actually probably don't need to up voltage at that level. I think most are able to just up FSB to 333 to get a 3.16 OC (like the 8400). If I were you I would try that and then see if you need voltage increase.