And yet....
Battlefield 3 - Ultra 4xAA - DoF 90 1920x1080
3 x 7970 = 150 fps avg. (costs ~1200 $ (399x3))
4 x 680 =131 fps avg. (costs ~2000 $ (499x4))
3 x 680 = 128 fps avg. (costs ~1500 $ (499x3))
2 x 690 = 124 fps av.g (costs ~~2000 $ (999x2))
More proof that tri and quad scaling on both side is messed up a lot, preacher would not approve. Two GPUs is the sweet spot
If PS4/Xbox 720 pull off an HD6670 level GPU, then I bet by 2014, 2x $600 Maxwell cards may be enough to last the entire console generation. The game changer could be if 2160P screen prices drop to affordable levels. However, it may be 5+ before that happens since they cost about $30,000-40,000 today. Perhaps I must not understimate the power of programmers to cripple performance with next gen console ports.
I'd like to say it's surprising that 3/4 cards are doing so poorly for both sides, but it's really not, this generation has done nothing but disappoint hardware wise, why would the drivers be any different?
Last gen you'd see diminishing returns from AFR and bottlenecking, but you'd still typically see advantages from the 3rd and 4th cards, this generation having more than two cards actually hurts you more than it helps.
Exactly, drivers are currently trash on the newer cards, my 470s scale very well, but I have a good cpu driving them. Scaling is as awful as it ever was though once you get cpu bound.
The 7xxx series paper launched in December 2012, eight months later and in OLD titles they're still failing. Nvidia isn't much better if any, I don't even care to look it's just awful.
/Praise the establishment
I myself was burnt pretty good by adding a third gtx 670 4gb, if some of you remember. Even at triple monitor resolution. the driver support just isn't there yet.