I seem to be have the same exact issue originally reported. When i maximize xchat it takes about 10-30 seconds to redraw the window. Also scrolling in firefox is extremely slow and delayed and choppy. Im running fedora 15 64 bit and im using lxde as my DE. Ive also disabled compositing in xorg.
Im not sure what else i can try...but this is becoming extremely annoying and i need to find a fix! Nvidia has always been good to me on linux up until recently...but i guess thats the name of the game when running a free os. If anyone has any ideas or suggestions please let me know.