Version: (using Devel) Installed from: Compiled sources Compiler: GCC-4.1.2 OS: Linux I didn't find an existing bug report corresponding to my problem so i'm adding one. I just updated QT, KDE and Nvidia driver at the same time so I don't know which one caused the problem. But since these updates, I have high CPU usage when compositing is enabled. Before my update, each core of my Core2Duo E8400 CPU were used at about 2 or 3%. Now it's around 25% for each core. There is no error message, but Ksysguard says that it's Kwin which is "eating" CPU ressources.
*** This bug has been marked as a duplicate of 154270 ***
What versions did you upgrade from and to by the way?
I dosn't seems to be the same bug. It's not Xorg which uses my CPU ressources but Kwin. Xorg remains at a normal level. About the updates. I updated QT from 4.4 to 4.4.1. KDE from a 4 days old svn rev, I think the rev was around 840300 to KDE rev 842797. And finally Nvidia driver from 173.14.05 to 173.14.12.
I just dowgraded the Nvidia driver to 173.14.05 and it didn't change anything. So the problem seems to come from QT or Kwin.
as you're using nVidia, pls try the following: activate direct rendering and deactivate vsync in the advanced settings. This solved the high cpu usage for me.
r850941