i assume that you have all the latest drivers?
have you tried turning up the screen refresh rate, it could be that you are producing the FPS but only scanning then in at 60Hz
Turn on Vsync. If there isn't an option in the game (I think there is) then you can force it to run with Vsync. If you turn on Vsync, it will decrease your performance somewhat.
If you have SLI...check your nvidia display in the SLI multi-GPU section. Check to see if the "Show GPU Load balancing" box is checked or not. It should be UNCHECKED. This should solve your problem if you are having the same kinda tearing I was having with the green lines. if not try the newest/different drivers.
Turn on Vsync. If there isn't an option in the game (I think there is) then you can force it to run with Vsync. If you turn on Vsync, it will decrease your performance somewhat.