OK, I understand better now, not that I know the answer. Sorry I don't
use DVI).

However, I did a quick search on "monitor scaling dvi", and I found
quite a bit of info - too much to quote here. There were some comments
that said that it is possible to fill the screen with the image, using
DVI. If you haven't already done so, have a look at a few topics. Or,
perhaps your monitor documentation can help?