BitFenix Spectre Pro Fan Review @ OCC
 

They took the Cooler Master HAF XM from being a case with great cooling to a case with nearly unbeatable cooling potential! Improving upon a case that already has such good cooling capabilities is no small feat – and on top of that, they did it without making a racket. Even running at full speed the BitFenix fans made relatively little noise compared to how much air they were moving. They don't make any annoying droning, whining, or ticking noises at full speed or at the 7v speeds.

http://www.overclockersclub.com/revi...x_spectre_pro/