i don't think SLI has anything to do wid just 1 card. i don't even think SLI will be really needed cuz it's expensive. i think that Nvidia and ATI is finding another solution for marketing multi-gpu's.
a waste of money unless you have lots to throw around. Id rather hope graphics card companys can come up with better ways to increase graphical performance rather than putting more cards in. Buy a sli mobo incase some new developments come about best to be safe.
SLI won't do anything extra for a 1-video card system, but it's a nice thing to have just in case. I'm getting it in my next system so that when the time for upgrades come I can just pop in a second video card and be done with it, lots easier and cheaper.
SLI Worth It Or Just A Waste of $$ 
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