Video Playback Corruption When Gaming Fullscreen

Any multi monitor setup i've ever had, has issues with running 264 mp4 video in full screen on one monitor while playing games or watching a slideshow (in media center) on another.

Xvid, or DivX video has always been fine for some reason, but now that most of my videos, tv shows and movies are in mp4 format, this problem is starting to become a nuisance.

Sometimes, on rare occasion, the video will be fine... but most of the time the video starts to scramble, or look corrupt ONLY once a fullscreen app is going, games that i can run in a fullscreen window are fine, which seems to be the only workaround

typical windows 7 x58 ssd nvidia system

does anyone have any insight?
thanks community