How do you figure the SP35s are cheaper? The price on 10 Prismas is 14.9BTC or 5960. To that you need to add 5*($45+$60+$3.50*8 + $10) for a DPS-2000BB/breakout/cables/shipping = $665
That's $6625 for 10 Prismas, which unless the SP35's have had a large price drop recently is still cheaper than two of those.
I used the numbers AM shareholder Mabsark posted here:
SP35 costs 4,035 USD inc. PSU + shipping for 6 Th/s at 3.5kW, it would take 147 days to break even,
10 x AM Prisma costs 9,250 USD inc. PSUs + shipping for 14 Th/s at 10.5 kW, it would take 158 days to break even, and
S3+ B9 costs 320 USD inc. PSU + shipping for 453 Gh/s at 355W, it would take 173 days to break even.
Ah, I see. Those are extremely poor numbers. The Prismas are a hair under $6000 right now, so that's factoring in $3250 for 10kW of power supply which is ridiculous. Even if you don't want to mess with server PSUs, you could go buy 10 well reviewed gold ATX supplies (RM1000/Capstone 1000M) for $1500 shipped from Newegg (plus tax, if you're unlucky).