The edges of the display are cut off. I looked at a few of the other responses, but my TV doesn't have those settings for the display (I have an element TV). I wouldn't really mind not seeing the full edges but it cuts off the time display and I can't tell the time.
41 Answer
You can tweak the overscan with xvidtune (from package x11-xserver-utils), but BE CAREFUL not to make big changes, you can ruin your monitor. Basically play around with the sliders, then write out the modeline, and add it to an xorg.conf to make the changes permanent.
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