Question: How to overclock a Q9450 and whats safe.

Well... I don't have any experience overclocking an Nvidia motherboard, but I can tell you that 3.0 is a very safe overclock with the 9450. You could probably do 3.2 pretty easy.

I only know intel boards, but the bios should be similar. Somewhere in the bios you need to change the the number 333 to 375 (with an 8 multiplier its 2.66 to 3.0). Its a very safe overclock, you should not need to change the voltage. However, if the setting is auto it may make the voltage to high.

So get CPUZ and see what voltage your q9450 is running at not overclocked (make sure the multiplier is 8, cpuz will tell you this. You need to make the computer run something to have it run at at 8 instead of 6.) Then plug in that voltage for you cpu in the bios when you overclock. Heat shouldn't be an issue even with stock cooling, i push my q9450 to 3.7 on air. If the computer crashes quickly then raise the voltage one increment.

its best to set the vcore to CPU VID thats what i do always before i start overclock.

if a safe oc on the 45nm cpus i will set 1.4V vcore being the max SAFE limit.but personally i will still push to 1.45v or 1.5v depend on load temp.