I tried the overscan and it works fine, until after I load a game, then it loses the overscan. When I exit emultationstation, I get the following message (also uploaded screenshot – http://imgur.com/xwA5xQ6)
Powering on HDMI with explicit setting (CEA Mode 4)
Frontend supports RGB565 – will use that instead of XRGB1555.
RetroArch[WARN] :: [GL] Stock GLSL shaders will be used.
Powering on HDMI with preferred settings
ondemand
(or at least that is what I think it says, I had to hook it up to a 40 inch monitor to read it as the left is cut off on the monitor I am primarily using – see this screenshot – http://imgur.com/MpUnpoZ – sorry for the poor screen shots, just trying to be quick)