Screen lag

Like i said, remove shadows

So you don't know your graphics card??

Graphics card would help, but are you talking about FPS lag? Or latency in your monitor? Cause I have never heard of monitor latencies being a problem.

is ASUS GeForce GTX 480 1536MB the graphics card?

only you know this! -_-'

I dont know anything about computers. i just play games

i got a ps3, but i think playing on pc is more fun

I think you are suffering from the game's stutter. That card is plenty good to play it. Play around with the config, or get master's tool. If all else fails, you will have to wait for the patches to fix it.