its not the GPU causing all that clipped off edges, the TV you hooked it upto is the one responsible for it.
I experienced this on a Philips 47" LCD TV. The format should've been on the remote and/or on the TV OSD menu.
I tried messing with the brightness and color sliders just to see if they would affect anything, but they did not either.
FYI - the color adjustment won't introduce any changes its just as it says it is, color adjustment not screen (size) adjustment.
and i can't find the model for your montior on this site
My 2 cents