What Vcore values have you tried? I'm using 1.28v for my 4.5ghz (1.25v crashed).
Well I'm using an ASROCK Pro4-m motherboard so I can only offset (i think). but I have gone up to at least +0.045 and I believe it was sitting around 1.28 or something while gameing.
Also, I just got my brother's i7-930 to overclock higher by under-clocking the RAM MHz. Would this work for me? I mean would going from 1600 MHz to 1067 MHz be worth an extra 0.3 GHz performance wise?