I just reinstalled my operating system (Crunchbang on Debian testing), and all of a sudden the fan is running as fast as it can even with 0% CPU. The air coming out of it is cold. The only CPU frequency governors available according to /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors are performance and powersave, and it was already set to powersave by default. What else could be wrong?


Have you checked your BIOS to see if there are any profiles set on the fans in your case? Sometimes these BIOS settings are a pain to override via the OS

  • No, there are no options in BIOS other than the standard boot options, date and time, etc. Also, just FYI, this is probably better suited for a comment than an answer. Jan 12 '14 at 23:57
  • Love to comment instead, but my new profile requires 50 rep before commenting ;) If it's not a BIOS issue, have you tried load-testing on and off to see if the fan spikes or lowers in speed? Jan 12 '14 at 23:59
  • If I start mining cryptocurrency (causes CPU to spike to 100%), the fan doesn't get any faster, but the air coming out starts to get somewhat warm. Jan 13 '14 at 0:07
  • Did you download new drivers for your motherboard once Debian was installed? It may be a driver issue then Jan 13 '14 at 0:13
  • I updated to testing as soon as I installed it, but it happens under Debian stable (and every other distro I've tried) as well. Jan 13 '14 at 0:18

Sometimes the only solution is to do a hardware modification. Buy a simple resistor and put in there, I did and now I can sleep again:)

This is true fact that some motherboards can not regulate fan speeds....

dont be such an angry nerd and vote me down!

It is not required... my cpu is at 47' ofcause you need to know what you do

  • At least until you start some CPU-heavy program that will fry it. You have prevented fan from spinning at full speed not only when it's not needed, but also when it's absolutely required.
    – gronostaj
    Jan 13 '14 at 0:39

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