Also I just bought this lol. For $265 on ebay so I will want to run it for a bit. My goal would be to mine enough to buy an S7 but that could take a while if ever.
maybe try relisting, maybe the person you beat in the auction will buy. see if you can get yourself 2 s5's would be more power efficient, which would allow greater profit thus a faster s7. im sure there are plenty on here people are selling.
Considering I would also have to buy a power supply for the S5s it would put the cost of ownership much higher than the s4 I bought.
Two S5 hashing power = 2300GHs. Only 300 more than my S4, not bad though.
Two S5 power draw = 1180 watts. Vs 1400 for the S4. A bit better power efficiency.
Cost to purchase two s5 units without power supplies = $160 per unit on ebay. So total of $320. Thats $60 over what I paid for the S4.
Cost to purchase two s5 units WITH power supplies = About $200 per unit. So about $135 over the S4.
Im too lazy to do all the math for the profit difference but I doubt its a large enough gap. Electricity will kill me though, but luckily I live in an area where I get .08kwh