I dunno about MCH voltage, it's kinda weird for me... used to be fine with mch 1.65v @ 400fsb but after overclocking to 425fsb @ 1.75v mch for a few hours with a subsequent crash I need 1.75v mch to run 400fsb (425 no longer works )

AHolland, I'd suggest looking into NB/SB cooling mod, which involves taking off the stock heatsinks and replacing factory thermal compound (dry stuff) with AS5 or something like that. After doing that I was able to hit 400fsb successfully. More details in this thread http://www.xtremesystems.org/forums/...d.php?t=106563