Originally Posted by 996gt2
4.5 GHz is pretty much guaranteed, even on air cooling. If you have a good chip you should be able to hit 4.7 or 4.8 GHz at voltages that are suitable for daily use.
I have a 2500K and ran it @ 4.4 GHz even back when I had a Hyper 212+. Now that I have an NH-D14 I have it at 4.5 GHz and max load temps never break 65C even in Prime95.
Just so you know OP 4.5ghz is not at all a guarantee. People on OCN tend to bandy that statement about because, I assume, you don't see a lot of bragging about mediocre overclocks on an enthusiasm forums, but the truth is that plenty of SB chips hit a wall at 4.4 or require stupid amounts of vcore to stay stable at 4.5ghz. There's a figure of diminishing returns out there (hopefully someone can link it) that shows what percentage of Sandy Bridge chips hit 4.5ghz and beyond, and it boils down to about 50% of chips can hit 4.5ghz and stay stable a reasonable vcore.
But hey, 50% is still pretty good odds. Not exactly what I'd call a "guarantee," but still, pretty good odds.