Random screen glitches

[Owltoid]

I'm sorry for the poor description, but I'm not sure how to detail the problem I'm having. Every once in awhile, my WoW will start flickering in small parts of the screen, almost showing little gray areas. It will continue randomly flickering (different parts of the window) until I restart WoW. Reloading the console will not fix the problem.

My screen setup (all on one monitor, my TV):

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Usually this problem start occuring when I switch my main window, such as:

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I cannot recreate the problem, and it doesn't happen all the time. I have tried turning down the video settings, but every once in awhile this still happens. Usually I'm in Dalaran or WG, so I know the video card is getting hammered, but for the most part everything runs smooth (25-40 FPS in Dalaran on main, 8 FPS on background).

My setup:
GTX 275 w/ 1.8GB
i7 920
SSD
12 GB RAM