Weird PMW fan problem - see if you can help out!

Hi All,

I am having weird problem with my mobo (or my fan).

My CPU fan is dead hence I bought a new PMW fan with 4 pin and connect it to mobo CPU_FAN but when connected the fan has this weird high pitch noise when booting (assuming fan speed is max). When it gets to Windows, fan speed slows down so the PMW is working and the sounds decrease (but still audible).

Here is the kicker, if i switch the fan to CHA_FAN (also PMW) the sound dissappear even when booting at max speed. The system itself works fine regardless of CHA_FAN or CPU_FAN.

While i am okay using CHA_FAN plug as CPU FAN PMW Controller, will it have any major negatives i need to concern about? Is there any workaround with this problem?


PC Spec:
i5 750@3.85 (offset +1.0vCore, 1.33vIMC)
P7P55D
G.Skill RipJaw 4GB
GTX460 (850core, 1700shader, 2000mem)
650W PSU
3 answers Last reply
More about weird problem
  1. Have you tried adjusting some fan options in the bios?
  2. It sounds like normal operation to me.

    Try using speedfan, a free app that can monitor and adjust fan speeds.
  3. Yes, Fan itself is working fine if plugged to CHA_FAN and there is no high pitch sound. It is only when connected to CPU_FAN the problem persist.

    BIOS detected the fan RPM as usual when its connected to CHA_FAN or CPU_FAN its just that i cant get rid of the sound when connected to CPU_FAN.

    I dont think the problem is with fan itself, i have also changed my PSU without any luck. For a temporary fix, i converted the 4 color PWM fan to standard 3 color fan pin and control it manually via my speed fan knob.
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