I am about to build a litecoin mining rig and I just wanted to make sure I am getting enough power for 6 beast gpus. I am currently planning on running two corsair HX 850s for a total of 1700w. Will that be enough or should I go for 2000w to be safe. I know the cards say you should have 300w but is that for just one card, does this include cpu, mobo, ram, ect.? Would 6 cards need 1800w? Thanks!