I have an original Xbox360 model and my friend has the new model(the one packaged with the Kinect). When trying to play two games, blue dragon and fallout 3, the game works fine on his xbox, but on my original hardware, the xbox cannot read the discs properly. For both games, it loads the game and then either gets a disc unreadable error, or constant lag and glitches ensue. My xbox plays all other games fine, but struggles with these two. Neither of the games have a lot of scratching that would make it unplayable, because the new model can still read the games fine.
This question is more of a fundamental hardware question: Do they read games differently, or in the same way? I was thinking that maybe the slider tray and read optic are arranged a little differently in the new model, but I have never taken one apart.