What resolution are you using?? You have a pretty good CPU, but the GT330 M is not that strong. I am surprised that you can play those games, especially Crysis Warhead at high. Maybe if you are using a laptop at 1360 x 768 you will be able to play them on high. Modern Warfare is fairly well optimized and runs well on lower end hardware, so you should be able to run it on medium to high.
My resolution is 1366 x 768, so i can play it at high settings then?