And just to tell you it also decreases the life of ur cpu by 30 to 40 percent if it dosnt work on cool temps even with a aftermarket cooler u need to be carefull
if u will be planning to overclock any time go for watercooling it is far better and will even run the i7 920 at cool temps even at clock speeds as high as 3.8 ghz but if you go for air go for the coolermaster v8 it will cost you around 90 usd and will run your cpu cool till about 3 to 3.5 ghz but if you want to go higher than that and protect go for water(liqued)