It seemed like a big deal when the Antminer T9 published the efficiency specification. It appeared to be much less efficient than the Antminer S9.
The Antminer S9 went through a version change in about October of 2016, changing from fixed frequency hash boards to variable frequency.
Bitmain also changed the warranty policy, extending it from 90 days to 180 days. But! If you have a bad hashboard on the new Antminer S9’s, you now have to send the entire box back to Bitmain in Hong Kong. You can’t just pack up all the bad hashboards into one big box and ship them back anymore.
After receiving a shipment of Antminer T9’s, I tested one against a fairly equivalent Antminer S9 variable frequency.
I made a video showing comparison of T-9 11.5 vs. S-9 12.0 (batch 16) variable frequency power draw at the wall. The T9 uses more power, but runs cooler.
At 210 VAC, room temp about 60 degrees F:
T-9 uses 1352 W, hashes at 11.5, highest chip temp 80C
S-9 uses 1329 W, hashes at 12.0, highest chip temp 94C
Not on the video, but:
Older S-9 fixed frequency at 11.85T used 1178 Watts.
S9 at variable frequency and 13.5TH (batch 17?) used 1390 Watts.