The board should take 16 months to pay off at today difficulty and exchange rates leaving eight months within warranty of guaranteed profit. The BFL-Single would take over eight months to pay off but with only six months warranty. Do the maths
Bitforce single:
830 megahash/second
80 watt
Heatsink + Fan
Comes with everything included: USB cable, Power adapter
Price: $599 + $34 shipping = $633
Icarus miner: (discontinued)
380 megahash/second
20 watt
Heatsink + Fan
Comes with everything included: USB cable, Power adapter
Price: $569 + $25 shipping = $594
x6500:
400 megahash/second
17.2 watt
No Heatsink/No Fan
Comes with no Power adapter or USB cable
Price: $550 + $7.90 mandatory insurance + $5.50 shipping + $17.95 AC Adapter + $8.95 USB cable + ($20 Two Zalman FPGA heatsinks + $4.54 shipping) + ($2.49 90mm case fan + $6.29 shipping) = $623.62
Sources:
http://www.amazon.com/Zalman-ZM-NBF47-Northbridge-Flower-Heatsink/dp/B000ZSBVK0http://www.amazon.com/90mm-Case-3-Pin-Connector-Black/dp/B004OFXXX8/ref=sr_1_2?s=electronics&ie=UTF8&qid=1333676747&sr=1-2Did I do my "maths" right?