In three of the four tests, the Freezer 64 Pro came within two to four degrees Celsius of the XP 90. Considering that the XP 90 is about double the price after you purchase a fan to mount on it, two to four degrees isn't bad. The Freezer Pro 64 is very quiet, almost inaudible when placed inside the case. It was also quite easy to install, and I did not have to cut the mounting clip on it to place it on the motherboard that it was tested on. If you have read any of my articles, you will realize that I'm a stickler when it comes to fan noise. I run three to five computers in my office at any given time and it can get quite loud; I am always searching for an alternative. I will be using the Freezer Pro 64 on the next AMD rig I build.