The issue is that the quadro 1800 costs $400 and the 580 costs $190. So if I can get a 580 and it turns out to be a bottleneck, I can just get any decent geforce bargain card, SLI it in, and be good to go.
What NVIDIA Quadro graphics cards can work together in an SLI configuration? Here are a few :
NVIDIA Quadro FX 5800, 5600, 5500, 4600, 4500, 4400, 3500, 3450, 3400, 1500, 1400, 560, 550, 540 and 350 cards are SLI enabled and can work in an SLI configured multi-GPU system. Two identical cards are required for SLI Frame Rendering and SLI FSAA .