If you are ever lagging when playing or find you stutter alot when you fire or anything. (I know I did) I have found your problem (Most likely) Basically my system specs are almost exactly the same as the recommended, so I pretty much expected to run this amazingly. However I got terrible results and the game ended up pretty much unplayable. The fix is to go to the settings tab ingame go to display and change the render device, im not sure what will give you better results so far the direct3d or software but for me the direct3d 9.0 gave me major lag. hope this helps, also try fiddling with your sound settings which can also free up some lag. Good luck and have fun 
