After upgrading my Debian from stable to testing, xorg is now less of a problem. However, the problem has not completely gone away and in some cases the cpu usage is still extreme.
Dolphine seems to work fine now, even with many folders and files in one view.
Let's start Firefox/Iceweasel and visit a twitter account page, for instance
Xorg cpu will reach 100% within seconds. Thing is, when I'm using Chrome, everything runs smooth.
Let's start amarok.... 100% cpu usage for xorg within seconds.
Some version info:
nvidia driver 285.03
May this info can help a bit in looking for a solution.