I have been using this cooler since my Pentium D 3Ghz. I have found this to be an excellent cooler for my Pent D, My E6750 and my Q9550. Under full load with Prime 95 and using, COre Temp, Real Temp and SPeed Fan to compare results I never got above 56 degrees celcius after full load for 1 hour. I highly reccomend this cooler. Although it is a bit loud, I always ran it at 3000 rpm for all tests.