Ok I had a Zalman CNPS7000 before this, and although it looked nicer and was much smaller, my Pentium D ran a little on the warm side. In Sisoft Burn-In sessions (15 Cycles of CPU Multimedia and arithmetic) it would hit temperatures as high as 54C although sisoft does stress both cores on my pentium d I wasnt comfortable with this temperature. Now since I switched over to this Thermaltake Heatsink, without the Ceramique even having a chance to set, Im hitting a mere 38C load with the same scenario. This to me is damned impressive, a 16C drop when I was using a pretty decent heatsink prior to this. I cant say enough about it, the install was a bit of a pain but other than that Im overly impressed right now. Its extremely quiet as well, probably about the same volume as my Zalman was. The one negative is that this thing is TALL. It clears my side fan in my case by less than an inch. If anyone has any questions let me know but I truely love this thing so far