Physical issues and proof it all works
The physical issues are nearly exactly like running SLI, except there's an extra monitor cable to attach to the rear of the PC and I don't connect them together internally. The XL isn't watercooled like the rest of my workstation, so there's issue with its noise, but when it's not working hard the display driver slows the fan down and I have full control over it using RivaTuner, which has no issue working with both GTX and XL at the same time.Power wise, the workstation's PSU - a Tagan TG480-U01 - has no problem powering both boards, even at the same time, and hardware wise it works without any problems.
You can see the XL installed underneath the GTX, with the Club3D DVI-to-VGA adaptor connected to the primary port on the XL, for output to the VGA input on the 200P4SS.
Proof
I've had more than one person tell me the following picture (click for the large one) is fake and Photoshopped, and that there's no way you can get ATI and NVIDIA to coexist. So much for belief that modern technology can work correctly, since not only does it work, but it works well. Three cheers for good OS engineers and driver writers that don't take liberties.
App windows shown, from left-to-right, top row then bottom: NVIDIA display driver main property sheet, Windows Display Properties Settings, Ultramon monitor wallpaper chooser, ATI CATALYST Control Centre, ATI Avivo Video Converter (requires an X1K-series board), RivaTuner 2.0 RC 15.8, and finally Device Manager.
The information you need to validate it's all correct is all there, from the GTX running in PCI Express 8x mode, three monitors shown in Display Properties and Ultramon, the dropdown in RivaTuner, and CCC controlling the XL with 200P4SS connected (which it's detected via EDID, with the Windows control panel showing a Plug and Play Monitor since I hadn't yet loaded the 200P4SS's driver by that point).
Proof of the 6.1 million pixels of display space (5120x1200), with awesome Ultramon taskbar across displays 4 and 2 (2 and 3 as you see them) ?
