Closed itself, error message but can't remember what. Anyway I have upped the core voltage to 1200 and it ran and finished fine.
However the Firestrike score is still about 600 less than what I got before I did the overclock!
So is the 3DMark11 and heaven scores which were fantastically high the ones to go off or the 3Dmark Firestrike which was lower than pre-overclock?
A little confusing really!
That's why its best to do it in small steps one clock at a time that way you can check for a performance drop more accurately and take appropriately action. Just stick the memory right back to stock and go back to your last stable clock and start again.
Oh and don't forget to make sure the power slider is at +20% you don't want your overclock getting throttled, that can causes crashes or letting you get higher overclocks than you really should.