system slow down while power plugged in

[DeoXMAN]

there is one problem with one laptop. when power cable is unplugged, system works fine, but when you plug power cable in, systems gets slower. i see it while opening folder in KDE, animation becomes slower, and so folders opens slower. i played around with power schemes - nothing. it happens only in KDE(i tested with Suse, mandrake and kubuntu), but with gnome it is ok (tested with ubuntu). laptop is sony viao.
can anyone help?

[MasonM]

It's obviously not a kernel related problem if the same effect happens with different distros, so I'd suspect a BIOS problem.

Have you tried updating your BIOS?

[DeoXMAN]

I dont think it is BIOS problem, because in Ubuntu with GNOME desktop everything is fine, as well as everything is fine with windows

[MasonM]

Doesn't mean it isn't a a BIOS related problem.

f it only happened with one distro I'd suspect improperly compiled ACPI options in the kernel, but that's not likely across several kernels.

It would be worth your time to check it out and see if in fact there is a newer BIOS version available for your machine/mother board. To solve a problem one must use a process of elimination, starting with the most obvious common element and working from there. The one most obvious common element here is the BIOS itself.

If that isn't it, one then proceeds from there. But as with any problem it must be approached and worked through in an organized and methodical manner and not by simply taking pot shots at it.

The symptoms indicate that it's most likely the cpu throttling is working backward from the way it should be. If directly changing these settings doesn't alter the behavior then one must look to something at a more base level. In this case start with the BIOS and work up from there.