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...