If only overclocking was that easy but there are no generic numbers that you can simply enter and be done with it.
Here's how I can give you a stable overclock, enable turbo
- it'll give you up to 4.1GHz
Because all CPU's have variance between them, to obtain a stable overclock for yourself there is no substitute for trial and BSOD's. What may work fine for someone else may not be close to stable in your case. Hell, it's possible (unlikely) that your CPU can't clock over 4GHz - throwing numbers out there to chase isn't my recommended procedure, IMO it's best to find a guide or two and see what you can get out of your CPU.
I think this is a good guide to get you started http://www.techinstyle.tv/20111319103/