I'm currently running a Zotac GTX 1080 TI AMP Extreme Edition rig with 6 cards, I'm using 1,7Kw/h with the entire rig power costs around R2200 per month.  I'm using Awesomeminer and running profit mining with an income of between R20k and R30k per month.  According to me the cards I have give the best Hash rates of all the 1080 TI's.