I have an explanation. No console, either Xbox or any other, need to run operating system. It only needs to run the game itself. This little fact is the key in superb graphics in any game. OS always eat some CPU power and certain megabytes of RAM. Then the rest of power is devoted to the game. Consoles have only one task to do. Moreover, it is to run the games, and they do that fantastically. This is why the Final Fantasy XI looks so good. this is why the games are always be better on consoles than on PC.