Fan speed - PMWOUT frequencies

[azagahl]

I was using SpeedFan and noticed that my CPU and case fans would be fully on at 1-100% power and be fully off at 0%. So I could only turn them on and off, not actually control their RPM's.

So I turned my WinBond chip's PMWOUT (power modulation wave?) frequencies from about 30 KHz down to 500 - 900 Hz. Then I could start controlling RPM's. I guess my mobo is set too high.

Is there any danger to using lower frequencies? Could this affect PC stability or wear out the motors?

I found that, generally, the lower frequency I go, the more effective the fan motors can be controlled. Some particular frequencies didn't work very well though - I guess this is dependent on the fan motors. Also, some frequencies produce an audible high-pitch hum - due to resonating components? - so those are to be avoided.