Quote Originally Posted by Martinm210 View Post
FWIW, the folks over at cystalfontz say this about PWM minimums on their 3 pin PWM fan controller:


Although they use a different type of PWM (also 3 pin), I can actually feel the fan kick on and off with their controller at lower settings. Anyhow, apparently there is at least some thought that low PWM is also not good for the fan. Perhaps low voltage regulation is no better for that either, but voltage is better for sound quality from the little testing I've tried.

I personally would rather get away from software all together and have an analog solution that uses voltage regulation. Anyone with multiple loops would probably want one control setup for each and may or may not have more than one PWM MB header and may or may not want to mess with extra software and background tasks to control that. I wouldn't mind if something could be programmed and shut down late, but I wouldn't like have to keep a process like easytune running in the background all the time.
this sounds as if they are using low frequency PWM. in this situation i can imagine it would be more stress to the fan and of course would generate this ticking sound. if PWM frquency is high enough (like intel spec which is using about 25kHz) there should be less to no ticking noise and no additional stress for the fan.

but anyway, i agree, using voltage control will ged rid of this problems and some others. this is why i decided to use voltage control instead of PWM control for 3-pin fans.

4-pin (real PWM) fans should not have this issues and thus can safely run under PWM control given the PWM frequency is chosen high enough.