weird. perhaps we have a similar problem.
here's my case.
got FX5200 agp . hooked up with 22" LCD. AGP works fine, it detects right resolution, but in DVI, there is no video in bios, boot, there IS video ONLY in windows and it only detects it as a HDTV with 760p resolution.
But this was not an issue with my BFG 6800 oc card and Ti4200 card. They both had perfectly functional DVI port.
hmm let us know if you find some solution.