Even though I only have 1 game that can stress my 1070 at 1080p (Space Engineers...and it actually does need as much RAM+vRAM as possible to display things with high settings at distances past the default 15KM), I'm still seeing a shitload of benefits.
Primarily in the form of HVEC and VP9 decoding, which actually means that my entire rig now consumes under 50W while watching Youtube (especially at 720p 60fps) and in the sheer fact that it has double the performance for half the power consumption in games. My now donated 970 kind of looks like a pig in comparison, since it was able to hit 200W with its small overclock (1379MHz over boost to 1401MHz).