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

[Pasi Kärkkäinen]

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