Bitmain's Antminer S21 XP Immersion: Full Hardware Overview

Bitmain launched the Antminer S21 XP Immersion on June 17, 2024 — the same day as its hydro sibling, the S21 XP Hydro. At 300 TH/s and 13.5 J/TH, the Immersion variant is purpose-built for single-phase immersion cooling deployments.

TLDR

• XP-tier efficiency for immersion deployments: 300 TH/s at 13.5 J/TH. Purpose-built for single-phase dielectric fluid baths, launched alongside the S21 XP Hydro on June 17, 2024.
• Breakeven electricity cost: ~$0.161/kWh at $52.18/PH/day hashprice (June 17, 2024). Strong margin across the full $0.04–$0.12/kWh industrial range.
• Lower per-unit power draw than the XP Hydro (4,050W vs 5,676W) — useful when individual circuit capacity is the constraint rather than aggregate facility power.
• The choice between XP Hydro and XP Immersion is infrastructure-driven, not performance-driven. The XP Hydro wins on efficiency (12.0 vs 13.5 J/TH) and hashrate (473 vs 300 TH/s), but it requires hydro plumbing. Immersion facilities deploy the XP Immersion.
• LuxOS support lagged launch. Operators should check current compatibility at luxor.tech/firmware before factoring firmware tuning into acquisition decisions.

Background

Immersion cooling has become a meaningful deployment format over the past two years as operators look to push density and extend hardware longevity. The S21 XP Immersion ships with a chassis optimized for single-phase dielectric fluid baths — different thermal management than the S21 XP Hydro's water-loop, designed to support facilities that have invested in immersion tanks rather than hydro infrastructure.

The launch timing was tightly coordinated. Both the S21 XP Hydro and S21 XP Immersion shipped on June 17, 2024, exactly two months after the Bitcoin halving. The two units share the XP-generation chip platform but target different cooling deployments. At 13.5 J/TH, the Immersion variant is slightly less efficient than the 12.0 J/TH XP Hydro — a tradeoff reflecting the thermal management approach. It's still meaningfully more efficient than the rest of the S21 lineup at launch.

Antminer S21 XP Immersion Specifications

Where the S21 XP Immersion Sits in the S21 Lineup

The S21 generation at launch of the XP Immersion, with its hydro sibling and the broader family:

The S21 XP Immersion sits second in the lineup on efficiency, just behind the XP Hydro. Both are XP-generation silicon, but the Immersion is configured for a different thermal envelope. For operators with immersion infrastructure, the question isn't XP Hydro vs XP Immersion — it's which cooling format the facility supports.

Hashrate-wise, the S21 XP Immersion's 300 TH/s puts it well above the S21 Pro and original S21 Hydro, while still below the XP Hydro's 473 TH/s. For immersion deployments, the XP Immersion offered the highest single-unit hashrate available at launch.

Hashcost Breakeven Analysis

USD hashprice was $52.18/PH/day on June 17, 2024 per HRI's Q2 2024 Report. The table below shows S21 XP Immersion daily profitability at that hashprice.

Based on $52.18/PH/day USD hashprice (Luxor Hashprice Index, June 17, 2024 — verified from HRI Q2 2024 Report). Calculated using S21 XP Immersion nameplate specs: 300 TH/s, 4,050 W (97.2 kWh/day). Breakeven electricity cost approximately $0.161/kWh.

The S21 XP Immersion generates strong margin across the full $0.04–$0.12/kWh range. Breakeven electricity cost sits at approximately $0.161/kWh — a meaningful buffer for industrial operators. The unit's lower hashrate per unit relative to the XP Hydro means absolute daily profit is lower, but profit-per-unit-of-power remains competitive.

Hydro vs Immersion: Which XP Variant Makes Sense?

The S21 XP Hydro and S21 XP Immersion are not interchangeable. The choice between them is driven by facility infrastructure, not raw performance:

• Hydro deployments use a closed water loop to extract heat directly from the unit. Best for facilities with existing hydro plumbing and rejection systems.
• Immersion deployments submerge units in dielectric fluid. Best for facilities with single-phase immersion tanks already installed.
• On efficiency, the XP Hydro wins (12.0 vs 13.5 J/TH). On per-unit hashrate, the XP Hydro also wins (473 vs 300 TH/s).
• On absolute power per unit, the XP Immersion is lower (4,050W vs 5,676W) — useful when individual circuit capacity is the constraint rather than aggregate facility power.

Fleet Efficiency Context

At 13.5 J/TH, the S21 XP Immersion sits firmly in the sub-19 J/TH top revenue-per-watt tier on Luxor's Energy Hashprice Index — with 5.5 J/TH of buffer below the tier boundary. In the post-halving environment of mid-2024, this efficiency tier was the dividing line between durable profitability and acute margin pressure. The XP Immersion sits well within the safe zone.

LuxOS Firmware Compatibility

At the S21 XP Immersion's June 2024 launch, LuxOS support was not yet available for this model. Luxor's firmware suite supports the broader S21 family (S21, S21+, S21 Pro, T21), but XP-tier support has historically lagged release by months. Operators should check current LuxOS compatibility at luxor.tech/firmware before factoring firmware tuning into S21 XP Immersion acquisition decisions.

Who Should Buy the S21 XP Immersion?

• Operators with existing single-phase immersion infrastructure who want to deploy XP-tier efficiency at 13.5 J/TH.
• Facilities transitioning from air-cooled to immersion deployment who need a flagship-tier ASIC purpose-built for dielectric fluid baths.
• Buyers with circuit-level power constraints where the XP Immersion's lower per-unit power draw (4,050W vs 5,676W for the XP Hydro) better fits available branch circuit capacity.
• Operators planning long-service-life deployments where the efficiency buffer below the 19 J/TH tier boundary protects margin against rising network difficulty.

Where to Buy

For S21 XP Immersion pricing, availability, and fleet-scale orders, reach out to Luxor's hardware trading desk via luxor.tech/hardware. Luxor's desk handles both single-unit and bulk institutional orders.

For live hashprice, real-time profitability calculations, and the latest ASIC market data, visit hashrateindex.com.

About Luxor Technology

Luxor delivers hardware, software, and financial services that power the global compute and energy industry. Its product suite spans Bitcoin Mining Pools, ASIC Firmware, Hardware trading, Hashrate Derivatives, Energy services, and a bitcoin mining data platform, Hashrate Index.

Disclaimer

This content is for informational purposes only, you should not construe any such information or other material as legal, investment, financial, or other advice. Nothing contained in our content constitutes a solicitation, recommendation, endorsement, or offer by Luxor or any of Luxor's employees to buy or sell any derivatives or other financial instruments in this or in any other jurisdiction in which such solicitation or offer would be unlawful under the derivatives laws of such jurisdiction.