Try it and see if you like the picture quality more or less then with it off. What it does it have the receiver pass to your TV the same resolution that a channel is broadcast in, so it's not involved in any up/down conversion. So try it and see which does that job better, the receiver or TV. One down side that I've seen is that channel changing will slow down since the box and TV will need to resync when the resolution changes where when it's off the resolution doesn't change.