KWin (KDE4 from rawhide) using way too much CPU (nvidia driver problem)

[Vini Engel]

Kevin Kofler said the following on 07/13/2008 04:49 AM:
> Vini Engel <vini <at> fugspbr.org> writes:
>> When I enable Desktop Effects kwin and xorg take about 30% of the CPU 
>> each. kwin sometimes takes as much as 80%, this is slowing down my 
>> machine heaps. Although I could just disable the desktop effects and 
>> resolve the problem I would rather give feedback to any KDE/Fedora 
>> developers out there and assist with the resolution of this issue.
>>
>> My machine is an "Intel(R) Core(TM)2 Duo CPU T9300 @ 2.50GHz" with 4GB 
>> of RAM and a "nVidia Corporation GeForce 8400M GS" with 128MB.
> 
> The proprietary nvidia driver is known to have absymal performance, and we 
> can't fix it because it's proprietary. Blame nVidia. There's nothing we can do 
> about it.

Well, it may not be the best driver out there but before Fedora 9 it did 
work very well for me. The fact is that my problem is not really related 
to performance, the overall performance of my machine is pretty good. 
The problem is that xorg and kwin use too much CPU, it doesn't bother me 
much apart from using more battery. If it doesn't jump up to 80% my 
machine goes ok, I have disabled some of the desktop effects and it 
improved.

I think we cannot blame nVidia for this because what is being used here 
is the CPU and not the GPU. Unless there is clear proof that their drive 
actually causes it to happen the problem to me will be related to the 
way KDE4 is handling OpenGL for its 'special' effects.

Vini