Unfortuanately the 200M is not very powerful. If it can be overclocked I imagine that it can only be a little and it will not have a large impact on performance. Are you sure your notebook only has the 200M? This page says that the MX6421 has the 200M chipset with dedicated X300 with 64mb for graphics:
http://support.gateway.com/s/Mobile/.../5956sp2.shtml
The X300 will perform a bit better than the 200M but it still not very powerful. It will run older games but it will struggle with newer games. To get games to run well you will have to turn down settings or drop resolution. I would be very surprised if you could get GRAW to run well with it even at lowest setting and resolution. System requirements on that game are very high. This is what Gamespot said:
"To give you an idea of the kind of stress GRAW can put on your computer, the machine we tested on, a Pentium 4 2.53GHz with 1GB of RAM and a 256MB GeForce 6800 Ultra, is considered mid-spec by the game. You're not allowed to even try to set the texture detail to high with a 256MB card--that's reserved for the pricy 512MB behemoths. The game still looks nice and sharp at medium detail, but as we mentioned, frame rates can drop precipitously when there are explosions or even just lots of enemies in the surrounding area. All of our gameplay was done at a modest resolution of 1024x768-- anything higher than that led to an unacceptable frame rate. We also tried playing with a minimum spec 128MB card--with this type of hardware, the texture resolution is noticeably compromised and frame rates are even worse"
Here is a good description of the different graphic options for notebooks:
http://www.notebookreview.com/defaul...ard+Guide+2006
Goodluck!