Pros: Moves a lot of air for a little fan PWM control keeps it quiet while the computer is idle

Cons: it is a little loud when it is running faster but it is tolerable and to be expected from a 40mm fan spinning at 9000 RPM

Other Thoughts: great for compact itx cases where there is no room for a larger fan

Pros: They provide excellent air flow for cooling my optical drives, that passive flow simply does not provide, given the power supply fan and case fan at he far side, and the power fan below, leaving a hot spot where the optical drives reside. I use four between the drives, BRD and DVR, and four above the hotter BRD, to keep the drives cool as cucumbers. And since DBA quantities are logarithmical, four, even eight, are not much louder than 1, and that is nothing compared to my input fans, which blow IN taking their sound in the airflow the flow. I find fully enclosed earphones sufficient to dampen all the al the noise. The white noise feature in my 'phones does so even further, bit my mind can also filter out background noise.

Cons: Noisy, but acceptably so.

Pros: was an easy swap for old parts.

Cons: Very loud. Sounds almost worse than my fan I replaced.