Well how did you compare? Because at least on skein, with same consumption, 1080ti is >100% of a 1070
I compare using best open-source miners with best acceptable speeds.
I used stable OC setting for 1070 and 1080ti: +95MHz core / 95% TDP / +450MHz memclock for high memclock algos (Equihash, Neoscrypt, etc) and -1000MHz for all others with low memclock speeds.
As for skein, the best speeds are with alexis78 ccminer: 1080ti makes 985MH/s at intensity 27, which is 70% more than 1070 with 580MH/s at intensity 25.5,
I dont really care about power consumption.
1080ti takes about 45% more power than 1070, but in overall profit power costs are only 2%, so I just ignore it.