As you can guess by the title I just bought a Sapphire Radeon 6790. It has 4 ports on the back. 2 x DVI, 1 x HDMI and 1 x Display Port. I had an XFX nVidia GTX 260 running dual DVI however dual DVI will not work on the 6790. I've gone through all the settings and removed/re-installed the display drivers. The second monitor is not present in Device Manager. Any thoughts?
got a spare DVI->DVI cable from a friend, and with a little trial and error got dual displays up and running. Apparently, the lower port next to the grill does not accept a VGA adapter, so my DVI cable went there, while an adapter+VGA cable goes to the top, port.