Still if 700 MH/s is what is sustains and it pulls 80W at the wall we are looking at 8.75 MH/W.
Even 80 watts is optimistic:
Consumes between 85 and 90w at full load.
Yeah but it may end up doing more than 700 MH/s. Was just trying to grab a middle of the road figure.
Best case scenario it does 850MH/s sustained @ 85W = 10 MH/W
Worst case scenario it does ~700MH/s sustained @ 90W = 7.8 MH/W
To look at it on a larger scale.
CPU Rig (i5-2600) ~0.2 MH/W
Casual GPU Gamer rig ~1.5 to 2.0 MH/W (single graphics card, high end CPU, a gaming rig used for mining)
High efficiency GPU rig ~2.5 MH/W (sempron, minimal build, linux on usb drive, 80Plus-Gold PSU, 3x5970)
Underclocked GPU rig ~5 MH/W (i.e. 3x 5970 550Mhz @ 0.8 VDDC)
BFL Single Worst Case ~8 MH/W (excluding host system power draw)
BFL Best Case ~10MH/W (excluding host system power draw)
Ztex FPGA Boards ~ 20MH/W (and other Spartan-6 based rigs, excluding host system power draw)
28nm "next gen" FPGA ~40MH/W (guestimate based on die-shrink of 40/45nm designs)
28nm SASIC ~60MH/W (guestimate based on power savings due to reduce gate count going from FGPA -> SASIC)
Custom 65nm ASIC ~100MH/W (based on "testbed" processor for SHA-2 testing)
Custom 45nm ASIC ~200MH/W (Moore's law applied to "testbed" processor)
Custom 28nm ASIC ~400MH/W (Moore's law x2)
Note: each data point is likely upper limit in its category and likely is overly optimistic but provides a rough estimate for SHA-256 efficiency.