Since I tried to set my computer too 800 mhz, where it used to run rather quiet, I observed a quite mysterious behaviour of Ubuntu: It sets itself to maximum frequency, after some time, not always the same. And not always directly to maximum, but in steps.
My CPU can run at:
2.00 GHz, 2.00 GHz, 1.60 GHz, 1.20 GHz, 800 MHz
(btw. the first 2Ghz is 100 Khz faster than the second 2GHz)
When I check the frequency, by using cpufreq-info or directly in /sys/devices/system/cpu/cpu1/cpufreq/ I can see, that it sets
of both CPUs to maximum frequency - 2001000.
When I set it back to 800000 - manually by editing the files or by using cpufreq-selector - it stays there for a while. Than sets itself to 1,6GHz and than to 2,0GHz... Not immidietaly tough - for some times, sometimes longer, sometimes shorter, it runs at 800MHz
Just after boot it is 800 MHz - set to performance governor always running at 2,0 GHz.
I have no idea where too look for, can't find anything in syslog, don't even know where it could come from. I wrote myself a script, that is changing the min_freq every other second, but well, that's no real solution.
And I can't find anything online, only about people where it sets itself to minimum frequency. Any hints, ideas, suggestions where I should start looking, which other processes could be connected to this are welcome!
ASUS Z53S F3SV Notebook
Intel Core 2 Duo 2GHz
cpufreq-info says "acpi-cpufreq" is the driver