Hmm, interesting.

My take is that NVIDIA usually provide the best support for Unix/Linux installations, at least in comparison with ATI/AMD. I have no NVIDIA cards that just won't work, but I do have ATI ones (OK PCI without the "e" )

SLI can be a bit strange as this box has NVIDIA graphics management software installed and NVIDIA onboard graphics, but an HD5670 graphics card and drivers. When I cold boot it goes to 1024x768 which is the lowest supported resolution and is a 4:3 aspect ratio, or 1.3333. 16:9 is 1.7777, and 15:9 (old PC widescreen standard) is 1.6666. It goes to 1920x1080 when I restart.

It is a 16:9 22" screen and worked just fine with a GeForce 8500GT card and SLI.

I have no idea what 1600x1050 is (apart from 1.5238:1), but I think that it should be 1600x900, which is obviously 16:9

Apart from possible attachment issues, I would recommend using "standard" settings to begin with.