CPU is hot and CPU fan making very many RPMs and much noise. (CPU fan not listed in speedfan)

CPU is hot and CPU fan making very many RPMs and much noise. (CPU fan not listed in speedfan)


On Saturday I replaced the motherboard of my computer because my old motherboard wasn’t working anymore. Everything went well, and after some tries my PC was booting and working! I noticed the CPU fan was making a lot of noise. I downloaded cpuid hwmonitor. The CPU was in idle state at 50 – 60 degrees Celsius. And the CPU fan was running at 6700 RPM!

After reapplying thermal paste two times (first time the pea method, then the card method, and then again), the CPU is still hot, but not that hot. If my PC isn’t doing anything, my CPU is around 30 – 40 degrees Celsius. But it is getting hot very fast. And the CPU fan runs about 4000 RPM. When I start a program, the fan goes to 6000 RPM.

I downloaded and installed speedfan to try and change the CPU fan’s speed. I can see the temperature of my CPU and I can see how fast the fan is going. This fan isn’t noted as “CPU fan” or something but as Fan 1. The fans are listed like this:

Fan 1: 0 RPM
Fan 2: 0 RPM
Fan 3: 0 RPM
Fan 1: 3500 RPM
Fan 2: 0 RPM
Fan 3: 0 RPM
Fan 4: 0 RPM
Fan 5: 0 RPM
GPU Fan: 1400 RPM

Why all those fans? I have only three fans (CPU, GPU, Power). In speedfan I can control only the GPU fan. And all the others aren’t doing anything when I change their values.

My question:
How can I make my CPU cooler and make my CPU fan make less noise and RPMs (my computer is clear of dust)? It would also be nice to know why speedfan isn’t working.


  • Motherboard: Gigabyte GA-970A-UD3 Rev 1.1
  • CPU: AMD FX-8120
  • CPU Fan: Stock AMD fan
  • GPU: AMD Radeon HD 6850


  • Windows 7

Note: I turned off Smart Fan for speedfan.

I fixed my problem. I had to replace my amd stock fan with a better one. I bought this one:


Thanks to this video:


I want to thank you all for your help and time you spent on helping me!

Best Answer

  • From the description it looks like faulty thermal control of the motherboard.
    Also, it’s not clear for me: did you applied just enough thermal paste or were generous with it?

    Solutions I see right now are:

    1. Update BIOS of your new MB. Quite often that does the trick on both cpu running too hot and fan not working correctly.
    2. If you used a lot of thermal paste it’s not good. Paste is not good thermal conductor, you should use as little as possible. In essence, it should fill micro-cracks and other imperfections ion the contact surfaces of both cpu and heatsink. If you did that already (use minimum amount of paste that is), no issue.
    3. Fan may have developed a fault. If #1 option is unsuccessful, check with other fan that is known to be working properly (just for tests, so it may be old one). But the cpu is mite too hot, so it may be it’s just compensating for that.
    4. Are you sure you connected the fan to the cpu_fan connector? I know… But better to make sure. You have quite a lot of connectors there.
    5. Make sure you placed and locked the heatsink correctly.

    I know most of what I wrote is really basic stuff, but please believe me, I made all of the errors above at one time or the other. If all that fails, it may be that new MB is faulty… I’ve seen that happen as well.

    Windows not genuine is normal after MB replacement – you need to contact Microsoft on that. They will sort it out.

    EDIT: afterthought – did you set up BIOS settings of new MB to default? Maybe it’s overclocking the CPU on current settings?

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