Summary: This fan actually replaced the OE fan on my CPU cooler. This is a HTPC setup, so quiet is more important than max cooling of a heavily worked CPU. The new fan doesn't move as much air as the original, typical of all the really quiet ones, but the computer loading isn't high either. If you need a lot of airflow, this is not the fan for you, but it is quiet...
Summary: I purchased 2 of these fans to replace the 3 pin fans I had on my CPU cooler, and yes they are quiet compared to the previous fans I had on there. I have an Asus motherboard with "Q-fan" which controls the speed of the fan via pulse-width-modulation (PWM) and when the fan control drops the speed below 1500 rpm's, there is an annoying high-pitched, whistling noise that the fans make.
A good choice if your motherboard has a 4-pin fan connector for PWM
R. Waller, Amazon
5 October 2013
Summary: Case fans with Pulse Width Modulation speed control are not widely available so if you need one, this is a good one. If your motherboard has a 4-pin fan connector, you probably need a PWM fan. Most of the available fans have a 3-pin connector and will only run at full speed if connected to a 4-pin connector. This fan runs quietly, increases speed under CPU loading, has a nice assortment of wiring adapters and fits correctly.
Summary: I replaced 6 fans in a Dell PowerEdge 2900 server (they had the noisiest fans ever, sounded like an airplane in mid flight). I found a YouTube video where a person replaced those fans with these ARCTIC F9 PWM fans, so I thought what do I have to lose. I ordered the fans, they came with free shipping, and arrived within a week. I spliced them in (as Dell uses a proprietary connector), and the fans were as quiet as could be.
Summary: I purchased two of these to replace some noisy old fans in my fathers computer. They worked great. I do like that you can use them for motherboards that only have on 4 pin connection for PWM. But, luckily, this motherboard has several.
Summary: This was a replacement for my stock CPU fan. Runs cool and quiet, on the stock heatsink for my Phenom X4. Installed easily, PWM and adapter for 3pin power was easy to use. I have recommended this product to my friends, and would do so again.