I've gone back down to 2.5ghz now. It's prime stable for 3 hours at least and passes all superpi tests. I've gone to 2.5ghz because its the highest I can get on stock volts.
I can't get above 2650mhz on 1.45v and can't figure out why. My memory is fine at 245mhz and at 2.68ghz, its only at 223mhz so that can't be the problem and my CPU can't be topping out there.