11.2 reducing CPU frequency and killing performance

Hi Board,

I have a Dell Precision M6400 laptop with an Intel Core2 Duo 2.8 GHz processor.

I have set Power Management to performance when on AC power and have also written a script that calls cpufreq-set to set the lower and upper limits to 2.80 GHz (cpufreq-info output below).

However, sometimes when doing some heavy work the frequency suddenly gets reduced to 1.60 GHz on both cores and I cannot set them back to 2.80 GHz using the script (cpufreq-set says errors occurred). Performance is then totally gone and I have to reboot. The same script then works fine after a reboot.

What is setting the lower limit back down to 1.60 GHz even though I set it to 2.80 GHz using my script? How can I stop/configure this or prevent it from happening?

Many thanks!

cpufrequtils 005: cpufreq-info (C) Dominik Brodowski 2004-2006
Report errors and bugs to openSUSE:Submitting bug reports - openSUSE, please.
analyzing CPU 0:
driver: acpi-cpufreq
CPUs which need to switch frequency at the same time: 0
hardware limits: 1.60 GHz - 2.80 GHz
available frequency steps: 2.80 GHz, 2.80 GHz, 2.13 GHz, 1.60 GHz
available cpufreq governors: conservative, userspace, powersave, ondemand, performance
current policy: frequency should be within 2.80 GHz and 2.80 GHz.
The governor “performance” may decide which speed to use
within this range.
current CPU frequency is 2.80 GHz.
analyzing CPU 1:
driver: acpi-cpufreq
CPUs which need to switch frequency at the same time: 1
hardware limits: 1.60 GHz - 2.80 GHz
available frequency steps: 2.80 GHz, 2.80 GHz, 2.13 GHz, 1.60 GHz
available cpufreq governors: conservative, userspace, powersave, ondemand, performance
current policy: frequency should be within 2.80 GHz and 2.80 GHz.
The governor “performance” may decide which speed to use
within this range.
current CPU frequency is 2.80 GHz.

Anyone have an idea on this?

Many thanks…