Zalman Poweroid TNN 500A PC
 

Quietness is generally a subjective issue, yet I feel confident in stating that the Zalman / Poweroid combination can't be heard above normal background noise. It's nice to hear birds chirp 30 feet away. It's nice not to have to dial the stereo up when listening to music, and it's nice that such quietness can be achieved without having to compromise performance

http://www.hexus.net/content/reviews...dXJsX3BhZ2U9MQ