Antminer S21 151 TH/s: Specs

BITMAIN's public model name for this air-cooled SHA-256 miner is S21, listed in the manuals as Model S21, Version L1-10. No official product is titled "S21 151T": 151 TH/s is simply one of the typical hashrate columns in the S21 user guide table, alongside 200, 195, 188, and 175 TH/s. Secondary marketplaces often label their units "S21 151T", which remains a bin nickname.

Official naming against marketplace labels

Source	How the unit is named
BITMAIN Support, "S21 Specification"	Version S21; glance hashrate 200 TH/s, 3500 W, 17.5 J/Ksol
S21 User Guide / Product Manual	Model S21, Version L1-10; typical hashrate row 200 / 195 / 188 / 175 / 151 TH/s
Trade and shop slang	"S21 151T", "S21 151 TH", matching no model field at Support

If an invoice says only "S21", read the hashrate the firmware reports and compare it to the published bins. A 151 TH/s unit is still an S21, neither an S21 XP nor an S21 Pro.

Figures for the 151 TH/s column

From the S21 user guide product-glance table, where every bin shares the same efficiency:

Typical hashrate	Power on wall @ 25 °C inlet air	Efficiency on wall @ 25 °C
151 TH/s	2642 W	17.5 J/T

The other columns of the same table, still for model S21:

Typical hashrate (TH/s)	Power on wall @ 25 °C (W)	Efficiency (J/T)
200	3500	17.5
195	3412	17.5
188	3290	17.5
175	3062	17.5
151	2642	17.5

The notes printed with that table state that hashrate, wall power, and efficiency are typical values, with a tolerance of ±3 % on actual hashrate and ±5 % on actual power and efficiency. The 25 °C reference is inlet air temperature, not room temperature.

The Support article "S21 Specification" publishes only the 200 TH/s, 3500 W, 17.5 J/Ksol line. For the 151 TH/s and 2642 W pair, the binding source is the user guide.

Shared S21 hardware envelope

These values describe the S21 server as published, so they are not specific to the 151 column.

Characteristic	Published value
Algorithm / coins	SHA256 | BTC/BCH/BSV
AC input voltage	220 to 277 V; out-of-range voltage may damage the miner
AC frequency	50 to 60 Hz per the guide; Support also lists 47 to 63 Hz
AC input current	20 A, on one AC wire
Required AC output power	4000 W per the guide
Network	RJ45 Ethernet 10/100 M
Size without package	400 × 195 × 290 mm, PSU included
Size with package	570 × 316 × 430 mm
Net / gross weight	15.4 kg / 17.2 kg, PSU included
Noise	76 dBA @ 30 °C, at maximum fan RPM
Max airflow	380 CFM; dust and poor ventilation reduce it
Operating temperature	0 °C to 45 °C
Storage temperature	−20 °C to 70 °C
Humidity	10 to 90 % RH, non-condensing
Altitude	≤ 2000 m; between 900 and 2000 m, subtract 1 °C from max temperature per 300 m

Support and the user guide disagree on the frequency range. Without the label on the unit concerned, record both values and have the serial number settled with the vendor.

What to verify before buying

A low bin like the 151 often resells cheaper per TH, which only makes it a good deal if the unit still holds its column. Four checks before paying:

1. The hashrate reported by firmware, read with the machine powered and up to temperature, not from a screenshot the seller supplied. The stated tolerance is ±3 %; a wider gap indicates a degraded board or a modified profile.
2. Measured wall power, compared against the 2642 W in the table, within ±5 %. Noticeably higher draw at the same hashrate means efficiency has been lost.
3. Consistency between the two, meaning a J/TH close to 17.5. It is the single number that summarizes the machine's real condition.
4. The electrical circuit available, since the machine wants 220 to 277 V and 20 A on one conductor, with a 4000 W supply recommended. A standard domestic installation does not qualify.

Two confusions to avoid when comparing listings: the S21 XP, which Support gives at 270 TH/s for 3645 W and 13.5 J/TH, and the S21 Hyd. and S21 Imm. versions, which belong to other cooling modes and other voltage classes.

Sources

• BITMAIN Support, S21 Specification: https://support.bitmain.com/hc/en-us/articles/23794895251609-S21-Specification
• BITMAIN S21 User Guide V1.2.5: https://file12.bitmain.com/shop-product-s3/firmware/c17a60d7-51c8-41a3-8365-b7e5d1506caa/2025/04/10/14/S21%20User%20Guide-V1.2.5.pdf
• BITMAIN ANTMINER Specifications index: https://support.bitmain.com/hc/en-us/sections/360002496253