I would like to let you (nv devs) know about what seems to be a driver bug.
First, i can't give any steps to reproduce. It happens too rarely.
I've never seen that before vdpau enabled drivers (180.06?).
It seems to happen after several days (or weeks?) of driver run. When it happens, It seems to happen after switching a vdpau window to fullscreen (the screen "freezes" for some seconds, then unfreezes and noise appears).
What happens is that a lot of "noise" is drawn on screen (all windows). The more i move a window, the more it's noisy (a window repaint cleans it). It's also visible on video, where i see moving black and white dots, very similar to analog noise.
I've made a screenshot and generated a nvidia-bug-report: