Why CPU fan speed is high?

Hi everyone,

My CPU fan speed is too high, around 4700 rpm, although the CPU is in idle state at 47 C.

CPU is Athlon X2 4800+, 2GB RAM, ATI 4890, Thermaltake 650 PSU.

Why is the fan speed this high? Can I control it somehow?
15 answers Last reply
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  1. Hello graphicsgriffin;

    Sounds like your CPU is running too hot.

    The fan is working VERY hard (running full speed) to keep it at 47C at idle workload.

    Fix the reason the CPU is running hot and fan speeds should be back to normal.
  2. Thanks for the reply, but I already cleaned the CPU fan and heatsink. Why should it try to keep it 47 C? This is not what happens with my system, I have been using it for 5 years. Idle temps used to be sometimes higher with no need to keep it at 47. There is some software doing this I'm sure.

    Is there any software I can tweak fan speed?
  3. And by the way, the fan speed started to fluctuate. Every some minutes it's 2100 rpm for a couple of second and then back to full speed.
  4. graphicsgriffin said:
    I have been using it for 5 years.
    Replacing the fan, or complete HSF should fix the problem.
  5. graphicsgriffin said:
    There is some software doing this I'm sure.
    Check your motherboard BIOS options.
    And also check the software that came with your motherboard.
  6. I installed fanspeed and now I set the fan speed to 2200 rpm with 100 % full load and the temp is 61 C. I think there is something wrong with the software controlling fan speed not the fan itself.
  7. I think it's the fan.
  8. Ok ... it could also be the motherboard.
  9. Is thermal paste applied properly, 61C full load is good
  10. Thanks for your patience. :D

    Yes this is the point, 61 full load at 2700 rpm is very good. Why then at idle with no fanspeed software it is working at 4600 rpms? Strange
  11. Maybe is the software that doesn't work too well

    Also after 5 years full cleaning of the heatsink and replacing the thermal paste should do the trick.

    If that doesn't work change the cooler
  12. What motherboard do you have? There should be something in your BIOS called "CPU Smart Fan" or "CPU Quiet Fan". It's a good way to keep the noise down.
  13. just save your money and get a liquid cooling system that are just for the cpu .
  14. Thanks all for the help.

    After I installed Speedfan, I sat the fan speed to 65 percent. Now the fan speed ranges from 1900 to 2400 rpm according to CPU load and ambient room temperature, just like the old days. It seems that the software that is controlling CPU fan speed is multiplying the speed for no good reason.

    As for the heatsink and the thermal paste there is nothing wrong with them since the temps are very good now which means that thermal conduction is adequate: 47 idle at 2100 rpm. As for a liquid system there is definitely no need for it regarding this particular problem.

    For now the problem is solved, but I will keep Speedfan running for a week and see what happens after that. Maybe I will have to run it permanently, or maybe the fan will break eventually!

    As for the BIOS, there is an option for something called Qfan. Anyway, enabled or disabled the problem is still there.

    My system specs:
    AMD Athlon X2 4800+ at 2.4 GHz, 2 x 1GB DDR-1 400MHz RAM, 650 watts Thermaltake PSU, Radeon 4890 1GB, ASUS A8N32-SLI DELUXE mainboard with nVidia nForce4 chipset.
  15. Update. Seems that the situation is still under control with SpeedFan runnin. I simply set the fan speed to 65 percent.
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