On stock settings, the GTX 1080 Ti FE outputs 32.04 MH/s. This is a bit better than the GTX 1070 which starts at 26 MH/s and can be overclocked up to 31-32 MH/s. The tests were performed using Claymore’s Dual Ethereum GPU Miner 9.4 on Windows 10 v1703 (which is considered the best Windows 10 version for mining).
Power Draw: 250-285 W
Now, we can achieve up to 35 MH/s in Ethereum if we overclock it (memory clock +300 MHz), 37 Mh/s memory clock +750. The power draw becomes about 10% more, so it goes hand by hand with the increase of hashrate. It can be undervolted by lowering power limit to 80% / 85% either 75% depends on the GPU if it can handle it.