But for me the Supermicro Server with dual Opteron 6348's and three Nvidia GTX 750's produces 1545 H/s and uses 426 watts. My electric cost is 7.4 cents per KWh.
The Monero profitability chart show a yearly profit of $465.
The Supermicro Server only cost me $252 and the three GTX 750's $120 for a total of $372. Payback is about 10 months. Realize though this hardware has value even if not for mining and that if I were to resell the server I would get well over $600 for it alone.