Bitmain Antminer S21 XP+ Hydro (395TH)

395 TH/s of SHA-256 hashrate at 5,925W continuous power draw and 15 J/TH efficiency. Built on SEAL02 chips with Bitmain's standard ±3% hashrate tolerance, meaning real world output ranges from 383 to 407 TH/s. ±5% power tolerance allows wall draw to reach 6,220W at peak. This is the top bin of Bitmain's S21+ Hydro family, producing 10 percent more hashrate than the 358 TH/s standard bin at identical 15 J/TH efficiency, same chassis, and same power envelope ratios.

MillionMiner uses "XP+" to designate the top bin of the S21+ Hydro family (395 TH/s) versus the standard bin (358 TH/s). Both variants share identical 15 J/TH efficiency rating. The XP+ designation is MillionMiner's internal naming. Most distributor channels (Mining Now, Intelion, MiningStore, OneMiners, asic-miner-profitability) list this product as "Antminer S21+ Hydro 395TH" or "S21+ Hyd 395TH" without the XP+ prefix. Bitmain's official catalog shows the unit under S21+ Hydro family branding. Buyers comparing prices elsewhere should search for both the MillionMiner XP+ naming and the alternative S21+ Hydro 395TH naming.

The S21 XP+ Hydro runs on 100 to 240V single phase power, compatible with standard commercial and high voltage residential circuits. This excludes the three phase industrial infrastructure requirement that applies to Bitmain's newer S23 Hydro series (launched October 2025, requires 380V+ three phase). For small to mid scale mining operations, facility renovations without three phase electrical service, hosting deployments in older buildings, or operators in regions with limited three phase residential availability, universal voltage compatibility is the practical difference between "can deploy" and "cannot deploy" on current hydro hardware. At 240V single phase and 5,925W, the unit draws approximately 25 amps continuous, fitting within standard 30 amp commercial circuits.

Different generations with different deployment requirements. S21 XP+ Hydro (this product): 395 TH/s at 5,925W, 15 J/TH, 100 to 240V universal single phase, November 2024 release. S23 Hydro: 580 TH/s at 5,510W, 9.5 J/TH, 380V+ three phase industrial, October 2025 release. The S23 Hydro leads on absolute hashrate (47 percent more) and efficiency (37 percent better). The S21 XP+ Hydro 395TH leads on universal voltage deployment flexibility and typically on acquisition cost per unit. For operations with three phase electrical service, the S23 Hydro delivers better lifetime economics. For operations without three phase, the S21+ Hydro 395TH remains the relevant option.

Different positioning within the S21 generation hydro family. S21 XP+ Hydro 395TH (this product): 395 TH/s at 5,925W and 15 J/TH. S21 XP Hydro 473TH: 473 TH/s at 5,676W and 12 J/TH. The S21 XP Hydro 473TH leads on both absolute hashrate (20 percent more) and efficiency (20 percent better) within the same universal voltage envelope. However, the S21 XP Hydro 473TH typically commands higher acquisition cost reflecting its premium positioning. For operators prioritizing per unit efficiency and willing to pay the premium, the 473TH wins. For operators prioritizing acquisition cost at still strong efficiency, the 395TH represents better value.

OD10 is Bitmain's second generation closed loop hydro cooling architecture deployed across S21+ Hydro and successor hardware. Key characteristics: closed loop water or water glycol circulation through internal chassis channels, external heat rejection through facility cooling infrastructure, standard plumbing fittings for easy deployment, sealed fluid path preventing contamination or evaporation losses, sustained performance under high ambient temperatures. Practical benefits: 50 dB operating noise (versus 75 to 80 dB for air cooled ASICs), more consistent chip temperatures extending component life, higher sustained hashrate without thermal throttling, longer maintenance intervals. OD10 represents Bitmain's refinement of hydro cooling compared to earlier first generation liquid cooled hardware.

External closed loop water cooling system. Required components: circulation pump sized for fleet flow rate (2 to 4 liters per minute per unit typical), standard industrial plumbing fittings, water or water glycol coolant, external heat rejection through dry cooler or water to water heat exchanger rated for cumulative thermal load (approximately 5.9 kW per unit, 20,135 BTU per hour), inline particulate filtration. For single unit deployment, a compact dry cooler and small circulation pump provide adequate infrastructure. For multi unit deployment, scale thermal rejection proportionally. Water glycol coolant costs significantly less than dielectric immersion fluid and uses commodity industrial equipment from standard HVAC suppliers.

100 to 240V single phase power, universal voltage compatibility. At 240V and 5,925W continuous: approximately 25 amps draw. Requires dedicated 30 amp circuit minimum for reliable continuous operation. At 208V (common North American commercial three phase feeding single phase breakers): approximately 29 amps. At 120V North American residential standard: not practical given 5,925W draw would require 50 amps and most residential circuits cap at 20 amps. Best deployment scenarios: standard 240V commercial single phase, European 230V Schuko, UK 240V BS 1363, Middle Eastern 220 to 240V commercial, North American 240V NEMA 6.

Possible but constrained. Requirements: dedicated 240V 30 amp circuit (most residential electrical service has one 240V circuit for HVAC or EV charging, adding another requires electrical panel capacity assessment), cooling infrastructure for 5.9 kW thermal load (typically a dedicated mechanical space or outdoor dry cooler installation), water cooling loop with installation requiring plumbing skill. Not practical on standard residential 120V circuits. For operators with appropriate 240V circuit capacity and willingness to invest in home cooling infrastructure, the 50 dB noise level makes the S21 XP+ Hydro one of the few industrial ASIC options deployable in residential settings. Otherwise, commercial or hosted facility deployment fits better.

Varies meaningfully with electricity rate. Multiple 2026 data points: Mining Now March 2026 at $0.07 per kWh: $14.43 daily revenue, $11.38 electricity, $3.05 daily net profit. asic-miner-profitability: $4.90 daily profit. OneMiners at $0.04 per kWh negotiated hosting: $7 to $10 daily earnings. MillionMiner $0.08 per kWh onsite calculator: $1.49 daily net. ROI estimates range 869 to 2,124 days at $0.07 per kWh depending on BTC price scenarios. At industrial hosting rates of $0.04 to $0.05 per kWh, 500 to 700 day ROI is achievable at current Bitcoin conditions.

10 unit deployment at 395 TH/s produces 3.95 PH/s at 59.25 kW total power draw. Per 100 kW electrical panel: approximately 16 to 17 units producing 6.3 to 6.7 PH/s. Compare this against alternatives at the same power tier. 100 kW of S21 XP Hydro 473TH: approximately 17 units producing 8.04 PH/s (better aggregate hashrate through higher per unit efficiency). 100 kW of S23 Hydro 580TH: approximately 18 units producing 10.4 PH/s (best aggregate at three phase requirement). The S21+ Hydro 395TH wins when universal voltage compatibility is binding or when acquisition cost per unit is binding.

Any SHA-256 proof of work cryptocurrency. Bitcoin (BTC) is the primary target. Other compatible coins include Bitcoin Cash (BCH), Bitcoin SV (BSV), Fractal Bitcoin (FB), Namecoin (NMC), DigiByte (DGB SHA-256 chain). Merged mining BTC alongside BCH and BSV through supporting pools (ViaBTC, F2Pool) adds marginal secondary revenue without reducing Bitcoin hashrate contribution.

50 dB operating noise, substantially quieter than air cooled ASICs at 75 to 80 dB. Comparable to a quiet office or rainfall at moderate intensity. Enables deployment in environments where industrial ASIC noise would be unacceptable: commercial buildings with occupancy, hosting facilities near residential areas, home deployments with appropriate cooling infrastructure, research or educational mining demonstrations. Note that the external water cooling loop (pump, dry cooler, circulation equipment) adds additional noise depending on cooling system design and location, so total deployment acoustic signature depends on cooling infrastructure selection.

Standard Bitmain hydro deployment. Step one: install dedicated 240V single phase 30 amp circuit with proper grounding. Step two: install and commission external water cooling loop including pumps, plumbing, coolant fill, and dry cooler or heat exchanger. Step three: rack or shelf mount the S21 XP+ Hydro unit and connect water inlet/outlet fittings to your manifold system. Verify zero leaks before energizing. Step four: connect PSU power cable and Ethernet management cable. Step five: power on, allow coolant flow to stabilize for 2 to 3 minutes, find miner IP through router DHCP client list or IP scanner, open Bitmain web interface at device IP. Step six: configure mining pool URL and Bitcoin wallet address, verify hashrate reaches 380+ TH/s within 10 to 15 minutes.

Standard hydro cooling maintenance. Weekly visual inspection of water fittings for leaks or corrosion. Monthly coolant quality testing (pH within spec, particulate levels minimal). Every 12 to 24 months full coolant replacement depending on fluid chemistry and water quality. Quarterly pump and dry cooler inspection. Inline filter replacement when pressure differential exceeds specification. Hashboard failure rates on hydro units run meaningfully lower than air cooled equivalents because chips operate at consistent temperatures rather than cycling with fan response. Maintenance simpler than immersion fluid management because water glycol is cheaper and more widely available than dielectric fluid.

Bitmain 12 month factory warranty on the complete machine covering manufacturing defects and hardware failures under normal operation within specified environmental ranges. Warranty exclusions include damage from coolant quality neglect, leaks caused by improper fitting installation, physical damage during cooling loop maintenance, power surge damage from inadequate electrical protection, operation outside the 5 to 45 degree Celsius range, and unauthorized firmware modifications. MillionMiner routes warranty claims through direct Bitmain channels. Document coolant testing schedule and maintenance logs to protect warranty coverage.

Yes. MillionMiner operates managed hosting facilities with single phase and three phase electrical service, water cooling infrastructure, and professional fleet management capable of supporting S21 XP+ Hydro deployments. Hosted deployment eliminates facility infrastructure CapEx (electrical service, cooling loop installation, rack hardware) and leverages MillionMiner's negotiated industrial electricity rates typically $0.04 to $0.06 per kWh versus $0.08 to $0.12 residential rates. Contact MillionMiner sales through the Get a Quote button for hosting pricing, capacity availability, and deployment timelines.

Any Stratum compatible Bitcoin pool. Foundry USA leads by network hashrate share. F2Pool has the longest operational track record and supports merged mining. AntPool is the native Bitmain ecosystem pool with deep integration. ViaBTC offers accumulation mode payouts for Bitcoin acquisition strategies. Luxor supports hashrate derivatives products. For fleet deployments above 5 PH/s (equivalent to approximately 13 units), direct negotiated agreements with major pools typically secure reduced fees below standard 1 to 2 percent rates.

CapEx beyond miner acquisition: 240V electrical circuit installation ($300 to $1,500 per circuit), water cooling loop infrastructure ($2,000 to $8,000 per rack depending on scale and existing facility infrastructure), basic rack or shelf hardware ($200 to $800). Annual OpEx per unit at 5.9 kW continuous: electricity at $4,152 at $0.08 per kWh, $3,633 at $0.07 per kWh, $2,076 at $0.04 per kWh industrial hosting rates. Water glycol coolant maintenance ($100 to $200 per unit annually). Spare parts and maintenance reserves (5 percent of acquisition annually). 3 year TCO per unit at $0.07 per kWh: approximately $4,042 hardware plus $10,900 electricity plus $900 maintenance equals $15,842 total. 3 year gross revenue at $0.07 per kWh profitability: approximately $3,340.

Within Bitmain S21 generation hydro: the S21+ Hydro 358TH standard bin for lower acquisition cost, S21 XP Hydro 473TH for better efficiency at premium pricing (12 J/TH), S21e XP Hydro 860TH for petahash tier universal voltage deployment. Within Bitmain next generation hydro: S23 Hydro 580TH at 9.5 J/TH, S23 Hyd 3U 1.16 PH/s for three phase industrial deployment, S23E Hyd 2U 865TH. For operators diversifying across manufacturers at the hydro tier: Whatsminer M73S+ 540 TH/s at three phase rack mount, M79S 1.35 PH/s at high power hydro tier. Cross algorithm fleet diversification: Antminer KS7 for Kaspa, Antminer L11 for Litecoin and Dogecoin, IceRiver AE3 for Aleo. For air cooled deployment at lower infrastructure commitment: Antminer S21 XP 270TH represents the single phase air cooled ceiling. MillionMiner's ASIC hosting service accepts S21 XP+ Hydro units at negotiated industrial electricity rates.