Virtually impossible to keep load under 0.5 on idle desktop with F14+kms

[Dennis Jacobfeuerborn]

Hi,
I just made a fresh install of Fedora 14 and it seems that KMS+gnome is a 
bit of a cpu hog. I can boot into runlevel 3 and the load will move towards 
0 but when I move to runlevel 5 and logging in the system always has a load 
of 0.5-1.0 even without starting any applications. The strange thing is 
that I don't see anything suspicious in "top" so I can't even say which 
application is causing the load exactly. Also if I boot with "nomodeset" I 
don't see this problem (though the desktop becomes completely unusable for 
regular work).
Any ideas what might cause this or how I could go about finding out more?
This is a system with an onboard NVidia chip but I'm using a Radeon R770 
based card with the defaults ("radeon" driver with no xorg.conf).

Regards,
   Dennis