some setting in your video card control panel should allow you to control overscan and set it to 0.
that is the only way to get 1:1 pixel matching picture. it is weird that it is not the default.
i have an ATI card so can't help you with specifics, but it was similar with it... plugging it in my HDTV, it looked roughly the correct size, but kinda crap. when i set the tv to exact pixel match, there was black space all around the image. in the catalyst control panel i found the overscan setting defaulted to some ridiculous non-zero value.