Agree with all the above, wait for GK110, the 6 series isn't much faster than the 580, 2x in SLi will last a good while yet.
It depends. In terms of pure performance perhaps not. However the GTX680 is far more power efficient than the GTX580 ever was. In my HTPC I originally had GTX580 SLI, moved to GTX580 Classified (fitting that in was.... tight!) then to GTX680. Moving to GTX680 meant I can move from AX1200 to AX850 (which has the fan in the right place for the vent on the side of my HTPC case) and I can run 3d mark 2011 or Witcher 2 w/ ubersampling without it sounding like an aircraft taking off. In fact under load I detect next to no increase in volume whatsoever despite having now overclocked. I see people saying to wait for the "proper" Keplar but hasn't it been established that will be aimed more at a specific compute segment and the GTX680 will be single GPU range topper through 2012? I'm not saying get the GTX680, it's probably not worth it for you. Bit harsh to dismiss it outright, though. It's possible that w/ a bunch of custom 4GB SKU's inbound and supply constraints easing you'll see something with priceerformance that makes it feel more worthwhile. CDJay
I'm curious what prompts you to ask whether it'd be a waste of cash. Are you actually not getting the framerates and image quality you want from your 580 SLI? If so, that could be fixed with 670 SLI. Only you can determine whether that increase in performance is worth it, as we don't have any info about your financial situation. You could probably get $500-600 for your 580's on ebay, the enough to pay for one and a half new 670's.
