Bitmain presented the air-cooled Bitcoin miner Bitmain Antminer T21 in November 2023. SHA-256 is the algorithm it was designed for, so it is a machine for Bitcoin and Bitcoin Cash. In our catalogue it is listed at 190 TH/s and 19.0 joules per terahash. At 17 kilograms, it needs a three-phase power connection.
Performance levels of the Antminer T21
- T21 190 TH/s at 3,610 watts (BTM-T21-190TH)
These figures stand for normal mode at an intake air temperature of 30 degrees Celsius. In high-energy mode the T21 goes up to 233 TH/s, drawing 5,126 watts and thus 22.0 joules per terahash.
Design, power connection and cooling of the T21
Without packaging the T21 takes up 400 × 212 × 290 mm; ready to ship, carton of 570 × 316 × 430 mm included, the weight rises to 19.1 kilograms. At full fan speed it produces 76 dBA; that is too much for homes or offices, and it belongs in a spot where nobody minds the noise and cool fresh air keeps coming in. It is operated at 0 to 45 degrees and stored at minus 20 to 70 degrees, with humidity of 10 to 90 percent.
Its power supply is fed from 380 to 415 volts at 50 to 60 hertz and never draws more than 12 amps; a 10/100 Mbit RJ45 socket provides the network link.
Braiins OS is available for the T21 too, letting you throttle each hashboard's consumption individually or push it for more hashrate. For 29.90 euros net per unit we flash it before shipping, provided the miner runs with you and not in our hosting. Changing the firmware ends the manufacturer's warranty, and our own warranty lapses as well.
As standard, Bitmain gives a 365-day factory warranty on the machine, counted from the shipping date; our standard price always includes our own warranty.
Comparison with the previous and next generation of the T21
Before the T21, the T series had the Antminer T19, which Bitmain presented in June 2020; the next generation is the Antminer S23. The three machines compared:
- Antminer T19: 37.5 J/TH (84 TH/s at 3,150 W)
- Antminer T21: 19.0 J/TH (190 TH/s at 3,610 W)
- Antminer S23: 11.0 J/TH (318 TH/s at 3,498 W)
From the T19 to the T21 the figure per terahash drops from 37.5 to 19.0 joules, and the S23 needs 11.0 joules. Somewhat more economical than the T21 is the Antminer S21 at 17.5 J/TH. The miner comparison ranks the T21 by daily revenue among all the machines on our site.
Verdict: Bitcoin mining with the Antminer T21
We have not had really good experiences with the T21. Hashboards failed again and again, and because that happened more often, spare parts were not always available right away.
On top of that, it needs a lot of power per terahash. It therefore makes sense mainly for operators with very cheap electricity; in return it copes well with high temperatures.
The Bitcoin mining calculator needs only your electricity price to show what the T21 earns per day in normal mode. Price movements and the Bitcoin network hashrate make this value shift every day; the cockpit tracks both and also lists the Bitcoin mining pools with share and fees.
