Laptop CPU overheating in Fedora, temperature +30 celsius higher than in Windows

José Matos jamatos at fc.up.pt
Sun Jun 12 17:20:55 UTC 2011


On Sunday 12 June 2011 16:56:33 Pasi Kärkkäinen wrote:
> Hello list,
> 
> Any tips how to debug why laptop CPU temperature is around 30 degrees
> celsius higher on Fedora 14 or Fedora 15 compared to Windows 7 ? Both
> Linux and Windows were idle when measuring..
> 
> I tried both Fedora 14 (Linux 2.6.35) and Fedora 15 (Linux 2.6.38).
> Laptop specs:
> 	- HP Elitebook 8530p.
> 	- CPU: Mobile Intel Core 2 Duo T9600 (Penryn).
> 
> Results:
> 	- Windows: CPU is 57 - 65 celsius when idle.
> 	- Fedora/Linux: CPU is 85 - 95 celsius when idle.
> 
> The laptop definitely feels much more hot when in Linux
> and sometimes shuts down with thermal overheating warning.
> That overheating problem never happens in Windows.
> 
> Checking "powertop" in Linux shows the CPU is mostly running
> with the lowest MHz available. Not much "idle" time though..
> 
> I was using "Core Temp" in Windows and /sys ACPI interface in Linux:
> 
> # cat /sys/bus/acpi/devices/LNXTHERM\:03/thermal_zone/temp
> 86000
> 
> # cat /sys/bus/acpi/devices/LNXTHERM\:03/path
> \_TZ_.CPUZ
> 
> "acpi -t" also shows the same CPU temperature.
> Fedora 15 Linux 2.6.38 dmesg here:
> http://pasik.reaktio.net/fedora/f15/cputemp/dmesg-laptop-f15.txt
> 
> 
> Any ideas how to track what's causing that? All suggestions welcome!
> Thanks,
> 
> -- Pasi

What is the graphics card?

I am running this from a laptop of the same model and I see:

$ sensors
acpitz-virtual-0
Adapter: Virtual device
temp1:        +30.0°C  (crit = +115.0°C)
temp2:        +50.0°C  (crit = +105.0°C)
temp3:        +26.6°C  (crit = +112.0°C)
temp4:        +58.0°C  (crit = +112.0°C)
temp5:        +46.0°C  (crit = +90.0°C)
temp6:        +16.0°C  (crit = +112.0°C)

radeon-pci-0100
Adapter: PCI adapter
temp1:        +58.0°C  

coretemp-isa-0000
Adapter: ISA adapter
Core 0:       +51.0°C  (high = +105.0°C, crit = +105.0°C)

coretemp-isa-0001
Adapter: ISA adapter
Core 1:       +50.0°C  (high = +105.0°C, crit = +105.0°C)

The only thing I have done in order to cool down graphics card was to run:

# echo mid > /sys/class/drm/card0/device/power_profile

instead of the default value auto (that alternates between mid (middle) and 
high) for the graphics card.

Definitivily I saw an improvement between F14 and F15.

Running the graphics card power profile as low brings the temperature even 
lower (at the expense of some slower window updates).

FWIW I never had a problem with overheating.

Regarding the comparison with windows (win.. what?) ;-) this computer came 
with freedos installed so no such luck here. :-D

-- 
José Abílio


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