I had the same problem...your card is fine here is a post from the tech forums on worldofwarcraft.com this fix works.
6. Video Flickering/Distortion after 2.1
If you are experiencing graphical distortions such as flickering of the video please temporarily turn off the Level of Detail...
http://www.performance-pcs.com/catalog/index.php?main_page=product_info&cPath=253&products_id=341
I just ordered this one myself...bill over at mnpctech uses this site himself so im assuming its the same one he uses...it looks slightly different than the pic you posted, but maybe it will suit...