Antminer S21 XP vs S21 Pro: efficiency or price per terahash
Same family, same firmware, same noise. The XP hashes harder per watt; the Pro costs meaningfully less per terahash. Your power rate decides.
S21 XP9.1
BEST AIR-COOLED EFFICIENCY
270 TH/s at 13.5 J/TH — the air-cooled ceiling. The machine that stays profitable deepest into difficulty growth.
Check XP pricing →
S21 Pro8.8
BEST PRICE PER TH
234 TH/s at 15 J/TH, usually $500–1,000 cheaper. The workhorse mid-scale operations actually deploy.
Check Pro pricing →
Side by side
Prices move with the bitcoin cycle — verified JUL 2026 via authorized distributors. BTC {{ price }}
Category winners
Expensive power (> $0.08/kWh)S21 XP
Cheap power, fastest ROIS21 PRO
Longest competitive lifespanS21 XP
First serious machineS21 PRO
Living-space friendlinessNEITHER — 75+ dB
OUR VERDICT
Run the math against your own rate. Below ~$0.08/kWh the S21 Pro’s lower price per terahash reaches ROI faster; above it, the XP’s 13.5 J/TH keeps margins alive as difficulty climbs. Buying several? Efficiency compounds — lean XP. Just want to learn? Neither: get a Bitaxe first.
Common questions
What about the hydro versions?
The XP Hydro (473 TH/s, 12 J/TH) and S23 Hydro (9.5 J/TH) lead the category but need liquid-cooling infrastructure — facility hardware, not a garage buy.
New or used?
Used S21-generation with test logs can be fine. Used S19-era machines at 20+ J/TH are a trap at 2026 difficulty, however cheap.
Where should I buy?
Bitmain direct or authorized distributors only — the ASIC gray market is full of worn and fake units.