Comment 125 for bug 363238

Just to add informations :
This problem was present in karmic, upgrading to lucid didn't change anything and I tried to manually compile the last stable radeon drivers (xf86-video-ati-6.13.0) and it still doesn't solve the problem.

So, at least for my board :
$ sudo lspci | grep VGA
01:00.0 VGA compatible controller: ATI Technologies Inc Radeon RV100 QY [Radeon 7000/VE]

with no xorg config file (wich means using EXA acceleration) and using a poor performance CPU, Xorg operations are sluggish, CPU usage is high (sometimes stucked at 100%).

I've tried all proposed solutions presented here, disabled all possible "bling bling" effects in gnome/kde and hardly got a few spare CPU cycles.
I'm unable to switch to XAA for a test has it seams to be disabled in recent drivers (log files show it doesn't care about my Option "AccelMethod" "XAA" and still talks about using EXA)
I'll have a try at finding an old driver version if XAA is still able to be activated with recent xorg version

Funny note for the end : It is so sluggish with EXA "acceleration", that I choose to just disable acceleration
(Option "NoAccel" "Yes")
This gives me better 2D performances, with the drawback of disabling OpenGL wich I need to renable with 2 xorg.conf files whether I want GL or not.
Maybe I'll have a try with the vesa driver ? :-)