Oh, well, even early B1 pulls just 1280-1290 at the wall with EVGA 1300 (at 120V), hashing at above B8 (4.83Th).
B5 does even better and B7 does 1345W at the wall with the same EVGA, which is not even a plat PSU, for 5.1 TH
oldies, but goodies, relatively speaking.
I am just saying...it went a bit downhill if you think about it...
It certainly did. Bitmain figured they'd squeeze the last drops out of the S7s by removing chips and applying a factory overclock to them to give us approximately the same speed. That brings efficiency and reliability down. I'm a victim of the lower reliability, and it seems I'm not alone. B8 seems to have a higher failure rate so far.
At 700MHz they're pretty much tapped out, and overclocking is not an option until we figure out how to control voltage. My OG S7s run at 6TH/s in comparison with overclocking.