La 980 andava il doppio della 780 che a sua volta il doppio della 680?
Non proprio.
http://www.anandtech.com/show/10325/...tion-review/32[GTX 1080] Relative to GTX 980 then, we’re looking at an average performance gain of 66% at 1440p, and 71% at 4K. This is a very significant step up for GTX 980 owners, but it’s also not quite the same step up we saw from GTX 680 to GTX 980 (75%). GTX 980 owners who are looking for a little more bang for their buck could easily be excused for waiting another generation for a true doubling[...]
GTX 1070 follows this same mold as well. NVIDIA is targeting the card at the 1440p market, and there it does a very good job, delivering 60fps performance in most games. By the numbers, it’s a good step up from GTX 970, but with a 57% at 1440p, it’s not a night and day difference.