If you've got a good cooler, you can get to 4.0GHz without any problems. Just a simple increase of multiplier to 20x and increase voltage to around 1.48v.
I've got mine running at 4.0GHz currently, with BIOS set to 1.48v but CPU-Z and Aida64 both show 1.488v. This chip can do much more, but I'm limited by my motherboard - I'm pretty sure you could get stable at 4.0GHz with much lower voltage or at a higher clock with the same voltage, but mine's stable and running cool so I haven't bothered.
nice and with my processor ive got a good cooler brought it shortly after getting the old one, only have the amd phennon x2 black edition but unlocked it all and runs at 3.51ghz stable and never had a problem so should be ok but if its not ill get a better cooler anyway thanks for the advice much appreciated