@anthony_c have you done any benchmarks to see what sort of rendering performance boosts you get from the SLI? I'm sure you're dying for Blender to add the ability to use combined GPU RAM.
@TARDISMaker Finally, another existing Debian user!
For almost 2 years, I've been using the following:
CPU: AMD FX-8150 (8-core)
RAM: 16GB 2100MHz DDR3
GPU1: ATI 7950 3GB DDR5 (Since 2.74 Cycles seems to like it a lot more)
GPU2: nVidia 650 GTX 2GB (Quick fix card for CUDAs, until Cycles was given better ATI support).
Note: Upgraded, finally.
Nothing great, but it does the trick. The CPU does great for those large renders, hence the reason I didn't even bother to buy a nice nVidia for Cycles. More or less for quicker/non-crashy Viewport rendering.
CPU: FX 9590 (8-core. As fast as the old ATI 7950)
GPU: nVidia 960 4GB
The new CPU is crazy fast, rendering scenes as fast as my previous GPU. The 960 of course runs like a dream.