holy crap you pay too much for power.. ive been watching my power bill since I got 4-5 cards going, only 3x 270x and 1 270 in one rig and another rig for gaming/mining in downtime with a 270 and its only gone up like 4$ with 3 cards and $8 with all 5...im using a EVGA supernova 1300 gold 80+ psu..  id be looking into gridseeds if I was you.. and sell me your used cards on marketplace