PWM Fan Noise

  • Just started the final details of my build….

    Hooked up axial flow fan to the FAN1 set for PWM control. Fan works fine but horrible noise when not at 100%.

    If I change the PWM value to something like 500 (seems to be the default for the online configurator) do I go higher or lower to possibly get the fan to quite down?


  • I would have thought trying a few settings would quickly determine the answer. My 120mm fan on my water cooler needed PWM frequency at 50 to be throttled back from 100% speed at all. Trial and error I suspect is the answer as fans are all different.

  • I tried going from 500 down to 250, didn't seem to make a difference in the noise. I guess since the micro controller directly handles each PWM output, I was going to try upwards but didn't want to go too high (wondering what the upper limit might be).

  • administrators

    Try reducing the PWM frequency to 100. But some fans just don't work well with PWM at all.

  • Thanks! F100 worked fine.

    I guess I didn't want to burn anything up search for an acceptable range.

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