There is an actual switch on the cables for the 360 that can be set to either SD or HD... make sure you have it flipped over to HD, otherwise you'd see what you seem to be describing.
|Originally Posted by briankmonkey|
are you 100% sure you have the xbox360 output set to 720p or 1080i? Many people have reported forgetting to set the switch.. Also, calibrating with an AVIA disc isn't going to help as much since you would be calibrating based upon 480i/p where as with the xbox360 you would want to calibrate based on 720p/1080i. Playing a DVD on the xbox360 does not upconvert to 720p or 1080i.