OK well it looks like you have the correct modules loaded. I was thinking maybe your configuration file was missing some needed modules loaded in order to fix the refresh rate. Because i know the last time I had a few problems with screen refreshing of dialogs and especially playing movies/videos I had disabled some modules to see if it was causing the nvidia driver to crash.
Hey that's one thought, tried using only the "nv" driver? If not try it and see, if that fixes it then nvidia's driver is yet again annoying the crap out of people. Good luck man. If that still doesn't solve it try disabling some of those modules to see if that has any positive effect.