I was just playing Medal of Honor. Every time I ran the framerate and my movement would become jerky. I use right shift to run (I'm left handed so use the right side of the keyboard for movement). I tried just holding the shift key and not moving - looking at the moving scenery (in this case trees waving in the wind) I could see the jerkiness.
I re-assigned the run key to a different key (delete) and this didn't cause jerking, but shift still did. I'd prefer to use shift for running so I need to fix this. Anyone else experienced this?