I've cleared pretty much all apps running in the background except for the essentials. I ran DirectX Diagnostic and everything is working fine. To tell the truth, I first started experiencing my problem after I installed Directx 9 awhile ago. But after I restored my computer, it switched back to Directx 8.1.
Funny thing is, I ran 3dmark2001 and everything seems to run normal--maybe a little choppiness--but I can definitely see the screen getting choppy during the Pixel Shader test for whatever reason. I still get a normal score (7600) so...beats me.
Any more suggestions, guys?