relatively quiet... The new 1U server I picked up for my CCTV / PBX system for the house is retarded loud. It has 8 of these bitches in it: http://www.sanyodenki.co.jp/en/news/2007/20071025sanace4048pwm.html It sounds like a damn jet is idling in my office closet. Looking for something that moves 7-15cfm and is quiet. 40 x 20mm will work just fine. Price doesn't really matter..