floydfan

sli/crossfire boards are technically capable of running either, but the driver limits sli to sli boards and crossfire to crossfire boards.

i dont know about crossfire on sli mobo, but i know there was a hacked driver that ran sli on a crossfire mobo, however the driver is pretty old, and would be incompatible with some video cards, mainly the 7950s and the 8800 cards. i wouldnt bother with such stuff anyways, multi-gpu is for benchmarking more than useful tech unless you game on a 30" lcd.

two mainstream cards arent worth running in sli, as you can usually get a similarly performing high end card, which will not require the expensive mobo, the higher psu requirements, and heat/space issues that crop up with using sli/crossfire.

just get a high end card, and when youre ready to upgrade, sell your old card and buy a new one. if you cant afford a high end card, get a mainstream card and save up for a high end one.