Typically, you should always try to output the native resolution of the TV. However, if you have the choice just output the signal in whatever that signals default setting is...as most high-end HDTV's will "usually" feature a higher-quality scaler than the hardware feeding the signal. For instance, if a game is native 1080i, and your TV is 720P...you will typically get the best image quality by sending the signal as 1080i to your TV and letting the TV scale the image down to 720P for the reason mentioned above.