I just installed a new GeForce GTX 650 in my computer, and I tried it out playing a few games like Mafia II, and it worked beautifully! But when I watch videos that are fast paced I see horizontal lines flickering on the screen (When in full screen). I'm using a VGA to DVI converter right now, if that's any help!
http://www.viewsoniceurope.com/uk/products/archive/vg710b.htm
That's the monitor I'm using:
http://www.viewsoniceurope.com/uk/products/archive/vg710b.htm
That's the monitor I'm using: