Okay, so lately I have been having this strange problem (for me at least) in almost every game I play (age of emipires III, black and white 2, bf2, and f.e.a.r..
I never had this problem before about a week ago, and I cant think of anything I did graphics wise. I have tried updating and using older drivers (my card is a nvidia 6600gt) but nothing helps.
Heres an example of what im talking about (not always this bad, and sometimes the specks are purple (the ground in bf2)).
(im talking about the green stuff...this was in slow motion in fear

)