For anyone who would like to silence a loud RB1100AHX2

These fans are almost silent and a night and day improvement over the stock fans in terms of noise profile. I also tried some of the Sunon 40mm fans recommended in other forum threads and found they are not much of an improvement over the stock fans.

http://www.frozencpu.com/products/16389/fan-1014/Noiseblocker_NB-BlackSilentPro_PM-2_40mm_x_20mm_Ultra_Silent_Fan_-_3800_RPM.html

http://www.blacknoise.com/site/en/products/noiseblocker-it-fans/nb-blacksilent-pro-series/40x40x20mm.php

It’s like a fan from 22nd century…