For some strange reason my computer likes to underscan when I connect to my 720p plasma tv over HDMI. it doesn't do this over VGA though.
The problem is, In order to play Blu-Ray disks my software FORCES me to connect over HDMI, and my TV doesn't support DVI.
I managed to get it close, but the pixel mapping is off so text looks ****ed up. I can't get it any closer, as the adjustments only go by 5% increments.