Antminer S1s with standard cp2102 usb to TTL serial connections, undervolted, underclocked:
I really like the stack, and 1.2W/GH from that is pretty impressive!
you might find some advantage to run the boards vertically oriented rather than horizontally - it will better force heat upwards and out
the plan is to get all my leftover boards done, and put them vertically into a case, this is just my test bench setup :-p
and we are working to get the watt/GH ratio downward even more :-p
sounds great - Im sure 1w/GH can be easily achieved, perhaps even 0.9w/GH - if you reduce the speed of each board to about 50GH with a bit more underclocking.
counter-intuitively, you might actually have better luck underclocking/undervolting if you don't cool it excessively. Its been seen in several different types of ASIC chips (spondoolies and bitfury for sure) that having the board temps above 40C sometimes provides better hashrates and stability then over-cooling the boards <35C