Thanks for all the replies guys. The below seems to have worked. Thanks Ace

Quote Originally Posted by Ace-a-Rue View Post
try 63-67% for CPU GTLREF...i read that the 45nm cpu's are designed to work at 63% for stock voltages...so...work from there up to 67% or 68%.
I set this to 65% and so far, so good. Does this mean that I will want to increase this whenever I increase vcore?

Maybe someone can give a quick explanation of what each of these extra voltages actually does?