I have a Mac pro I use for color grading work with DaVinci Resolve, this software required me to configure this machine with 2 GPUs, one that handles the computer displays and one more powerful that is used by the software to do the color work... In my case I used a simple GT120 to power the displays, and a Quadro FX for the workhorse processing unit (no screens plugged into it).
just recently I began using this machine for some performance work as well, using Jitter. And I'm curious to know how gl objects deal with multiple GPUs, do they see only one? and if so, which one? Can I force Jitter to use the more powerful one, or does it already do this on it's own? also, where should I be plugging my projector(s) in? in the quadro dvi ports or the GT120 ports?