To tell you the truth, with the C2Qs and C2Ds, the big factor is the motherboard. You could hit most of those speeds with a stock cooler. These things, do NOT run hot at all. My C2D has about a 1ghz overclock, and the one thing that is stopping me from going further is the motherboard. I know that these e6300s can hit 3+ ghz on some motherboards. My old one couldnt hit 2ghz, same processor though. So make sure you buy a good overclocking motherboard! DFI mobos are pretty good for it, the nforce 6 and 7 series are both pretty good for overclocking.