Shrug, I hope you two pinpoint the problem.
Of course we'll pinpoint the problem.. going to investigate right now.
Nicolas, what apps are slow on your machine? Can you send me a copy of your xorg.conf off-list just in case (although I think this focus on the nvidia driver is going in the wrong direction), considering that this is *patterned* behavior of *GNOME* *GUI* applications, which everyone seems to ignore. It's probably some sort of gtk/cairo craziness that's making it slow. I can now confirm same behavior on giFT and BitTorrent file sharing tool (gtk2 apps).
You know what the worst part is - the screensaver. I've been wondering for a while why I must endure the black screen with no response for like 20 seconds after I move the mouse, and this is most likely the answer. Now I just need to figure out why it happens. Something in the last few weeks of upgrades broke it. I haven't done upgrades for that time, since I was stuck at 128MB RAM and yum took forever to do anything at all...but, for the record, the screensaver worked properly.