Sure enough when I fired up ShootMania, no bad polygons! I've been playing for hours and not one crappy polygon! So it turns out it was the GTX 660 that I had which caused this problem.
It's still strange that the polygons would only happen in this game and no others. But nonetheless, it only took $400 to resolve the issue playing a $20 game. That sounds about right...
Thanks for all the help! I'm off to play
