I wouldn't overclock just yet, don't see it necessary unless you are rendering and stuff like that which requires massive amounts of CPU power I doubt any games will gain performance from sandy bridge CPU's when overclocked....I don't think they reach their limit, from todays games....
Pushing a i7-2600K to 4.5 Ghz is such a no-brainer if you have a decent motherboard, stable power supply, and slightly better heatsink (air) than intel supplies. Since the CPU, with standard power management settings, only runs at MAX throttle when it's doing "real" work, you never really stress the thermal limits of the processor. I do however notice a difference between running it at stock (3.4 Ghz) vs. 4.5 Ghz. - even in normal non-gaming situations.
Psh fire up world of tanks and tell me it does not want clock speed. If you can run good settings and not peg a core do tell me what you are using as omg do want. Need a stable 60FPS to count... no drops to 30 (as I get running 4.0 875k)
I doubt any games will gain performance from sandy bridge CPU's when overclocked....I don't think they reach their limit, from todays games.... 