# [solved] Overworking laptop fans

## maiku

Recently I bought a Dell Studio 1537 laptop which had Windows 7 on it for a day before I put Gentoo on it.  When I was using it on Windows 7 the fans were pretty quiet.  However when I put Gentoo on it the fans continually spin pretty darn fast despite being idle with only 16 processes running and on ondemand CPU scaling.

Did I miss a fan control option somewhere or are these some legitimate heating problems going on here.  I doubt dust collected in the fans in the day that I've had it...

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## pianosaurus

Check that the CPU is actually running at a low frequency, and that the temperature is not actually too high. Here's what I have under moderate load (completely different machine, though):

```
# grep MHz /proc/cpuinfo

cpu MHz      : 800.000

cpu MHz      : 800.000

# cat /proc/acpi/thermal_zone/*/temperature

temperature:             55 C

temperature:             48 C

temperature:             43 C

temperature:             45 C

temperature:             28 C

temperature:             50 C
```

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## maiku

When I start up the machine to when it is in heavy load, this is all I get:

 *Quote:*   

> # cat /proc/acpi/thermal_zone/*/temperature
> 
> temperature:             27 C
> 
> temperature:             0 C

 

The CPUs when idling are *Quote:*   

> # grep "MHz" /proc/cpuinfo
> 
> cpu MHz         : 933.000
> 
> cpu MHz         : 933.000
> ...

 When I start up the machine it's silent.  Then the fan gets louder and louder until it's quite audible.

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## maiku

The fans function as normal when X is loaded with the fglrx driver.  I'm not sure why, but it works.

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## pianosaurus

In that case, it seems it's not your CPU that is running hot, but your GPU. It probably has its own fan. I have switched to the open source drivers, so I can't check this, but I seem to remember the ati drivers ship with a tool you can check GPU temperatures with. Something like aticonfig --pplib-cmd "get temperature 0"?

Actually, it's probably not running hot at all, but the system doesn't know that until the driver is loaded.

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## maiku

It returns something like  *Quote:*   

> Temperature for thermal controller 0 is 50.500000

 which in fact is much hotter than the CPU.

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