Antminer S21 XP: Specs and Analysis

The Antminer S21 XP (BITMAIN product glance: version S21 XP, model 10) is an air-cooled SHA-256 ASIC sold by BITMAIN for Bitcoin and other SHA-256 coins. It is a distinct SKU from the air-cooled S21, the S21 Pro, the water-cooled S21 XP Hyd, and the immersion variants. The figures below come from BITMAIN Support and the BITMAIN Shop product page.

Manufacturer typical figures

BITMAIN publishes typical values measured at 25 °C inlet air. Support and Shop agree on tolerances: typical hashrate may vary by ±3 %, power on wall and efficiency by ±5 %.

Quantity	Typical value
Typical hashrate	270 TH/s
Power on wall @ 25 °C	3645 W
Power efficiency on wall @ 25 °C	13.5 J/TH (Shop); the Support table labels the same number J/Ksol

Those 270 TH/s and 3645 W are not a guaranteed continuous output. Inlet air above 25 °C, altitude, dust, and fan RPM all shift measured wall power and J/TH. BITMAIN Support publishes hashrate and J/T curves against ambient temperature, without transcribing their points into the HTML table.

At 13.5 J/TH, this model sits between the hydro flagships, around 9 to 12 J/TH, and mainstream air at 16 or 17 J/TH. That figure, not the hashrate, determines the electricity price above which the machine stops earning.

Electrical and mechanical

Unless noted otherwise, these lines come from S21 XP Specifications:

Characteristic	Published value
Algorithm / coins	SHA256 | BTC/BCH/BSV
AC input voltage	220 to 277 V; out-of-range voltage may damage the server
AC frequency	50 to 60 Hz
AC input current	20 A, single-phase
Required AC output power	4000 W
Network	RJ45 Ethernet 10/100 M
Size without package	449 × 219 × 293 mm
Size with package	640 × 360 × 450 mm
Net / gross weight	18.7 kg / 21.5 kg
Noise	76 dBA, fans at maximum RPM
Operating temperature	−20 °C to 45 °C
Storage temperature	−20 °C to 70 °C
Operating humidity	10 to 90 % RH, non-condensing
Operating altitude	≤ 2000 m; from 900 to 2000 m, maximum temperature drops 1 °C per 300 m

The Shop listing repeats the same 270 TH/s, 3645 W, 13.5 J/T, 220 to 277 V, 18.7 and 21.5 kg, and the −20 to 45 °C range. Some mechanical cells there differ from Support, notably packaged size and a 450 mm length. While the two official pages disagree on millimetres, measure the unit you receive rather than deciding from documentation. Shop also lists a maximum airflow of 550 CFM, absent from the Support table used here as the primary source.

Nearby models not to confuse

• The S21 XP Hyd is a separate liquid-cooled product, rated by Support at 473 TH/s typical, 5676 W at 35 °C inlet water, 12.0 J/T, and 380 to 415 V AC. Those figures never apply to an air S21 XP, and the confusion is common in resale listings.
• The air S21, whose Support headline bin is 200 TH/s for 3500 W and 17.5 J/Ksol, belongs to a different version line.

Before installation

The manual attached to the Support page identifies PSU APW171215 as part of the S21 XP server, and calls for an ANTWIRE-20SP cord to a PDU. Three things to settle before powering up:

1. The electrical circuit, sized for 220 to 277 V and 20 A single-phase, with 4000 W of capacity. A standard domestic socket does not qualify.
2. The source of firmware and IP Reporter, downloaded from BITMAIN's official pages rather than a third-party mirror, otherwise you install an unaudited image.
3. Noise and space, at 76 dBA on maximum fans and a 449 mm chassis weighing 18.7 kg, checked against your rack or your host's constraints.

The choice of pool, worker, and payout address stays independent of the chassis and can be made after installation.

Sources

• BITMAIN Support, S21 XP Specifications: https://support.bitmain.com/hc/en-us/articles/35383015643673-S21-XP-Specifications
• BITMAIN Support, Antminer S21 XP: https://support.bitmain.com/hc/en-us/articles/38059223529241-Antminer-S21-XP
• S21 XP Manual V1.0 (APW17) PDF: https://support.bitmain.com/hc/en-us/article_attachments/38059219790617
• BITMAIN Shop, Bitcoin Miner S21 XP: https://shop.bitmain.com/product/detail?pid=00020250909103743899t7Ovlywi073C
• BITMAIN Support, S21 XP Hyd Specification: https://support.bitmain.com/hc/en-us/articles/34523540504857-S21-XP-Hyd-Specification