Ah i sorted it,Messing around with the Physx must have screwed the drivers up...uninstalled the Nvidia drivers and re-installed them and it runs perfect now.
as for overclocking the Cpu,Its stock atm and the games ive been playing have run better than on my Q6600 @ 3.5Ghz
,Quite a boost so cant wait to see what improvements overclocking to say 3.6Ghz brings. 
as for overclocking the Cpu,Its stock atm and the games ive been playing have run better than on my Q6600 @ 3.5Ghz