hmmm question (how well can a MacBook play games)

http://youtube.com/watch?v=xpma495NOqo ok so in that video that guy plays a couple of games on a mac using boot camp to use windows but i thought that the macbook didn't have a very good graphics card and CS needs Directx 7 to play and only 256 mb of ram, so how does a macbook paly it i mean it has more then enough ram so why do u need 2 GB of ram? and how does it support those graphics with a bad graphics card with virtually no lag? (sorry if that made no sense)