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Field report · Oct 25, 2026 · 5 min read
Two years in Argentina, never switched off: hashprice never reached the Antminer S21 Pro's line
The S21 Pro was bought on 8 October 2024 and has run every day since at Argentina's 6¢. Hashprice bottomed at $27.74 in June 2026, $5.06 above its power line. Nigeria is about 20% ahead on the year, which is not yet enough to send it.
Bitmain Antminer S21 Pro (234 TH/s)
Bought for $4,472, it has kept 0.0874 bitcoin and never stood idle
The Antminer S21 Pro is Bitmain's air-cooled follow-up to the S21. Bitmain announced it on 29 March 2024 at 234 TH/s and 15.0 J/TH, against 17.5 J/TH for the S21. Our store lists the 234 TH/s model at 3,510 W in an 18.5 kg case 400 mm long, 195 mm wide and 290 mm tall. Bitmain's own specification page would not open for us, so those figures are our store record.
We hold its first settled price on 8 October 2024, six months after the April 2024 halving: $4,472, or $6,140 landed at our Argentina site. In the 748 days since it has mined and kept 0.0874 BTC, worth about $7,081 today, for $3,918 of electricity. That is $3,163 of cashflow with every coin kept, or 52% of its landed cost. It is two years into a four-year life, and this report says how far through the box it is, not that the box is paid for.
Hashprice stayed above its power line every day since it was bought
A machine's line is the hashprice at which a petahash of its hashing stops covering its own power. For the S21 Pro that is $22.68 a petahash a day at Argentina's 6¢ and $14.74 at Nigeria's 3.9¢. On the day it was bought, our hashprice chart read $45.84.
The lowest reading since is $27.74, on 6 June 2026, with bitcoin at $60,771. That is $5.06 above the Argentine line. On 23 October hashprice was $36.53. A 15 J/TH machine has not needed a day off. The same test for a 19 J/TH machine has its own page.
The worst day of the last two years left the S21 Pro $5.06 a petahash clear of its power bill.
The margin shrank faster than the coins did
Coin output slid more gently than profit. In the 85 days after it was bought the S21 Pro made about 0.0045 BTC every 30 days. In the third quarter of 2026 it made about 0.0034. A petahash earned 0.00073 BTC a day when it was bought and 0.00045 on 25 October, so the network pays less for the same hashing, and that is the fall in the machine's coins.
Cash left after electricity at 6¢ shows it more sharply: about $7.41 a day across the 85 days of 2024, $6.47 a day in 2025 and $2.78 a day in 2026 so far. It stayed positive every month, through bitcoin's $124,493 high on 6 October 2025 and its $59,014 low on 30 June 2026.
Nigeria is ahead, but not by enough to move it
Every machine we host crosses to Nigeria once, when a full trailing year says cheaper power is decisively the better home, as the guide to the crossing sets out. Over the last 365 days the S21 Pro would have made about 20% more after electricity in Nigeria than in Argentina, because 3.9¢ power outweighs Nigeria's lower uptime. The crossing rule asks for a wider gap than that, so it is still in Argentina.
Today a coin costs it about $50,500 of electricity at 6¢ and about $32,800 at 3.9¢. The gap is real, and the crossing will come when a full year says it is wide enough.
What a fault would cost it here
We found no operator survey of S21 Pro failures, so its durability is unknown rather than good. What exists is a repair shop's reference on the S21 family. D-Central's hashboard repair guide says its failure patterns are reported by the community and are "not an internal failure rate", names thermal-shock solder cracking as the headline finding, and notes that the chips form one chain, so "there is no partial-board mode".
That describes a hashboard swap. Hosted in Argentina a repair is billed at the cost of the part, which is the case made in the guide to failed hashboards. Across two years of running this machine has not been switched off for any reason.
What is left, and what it says about the next machine
To the April 2028 halving, at today's difficulty, the S21 Pro has another 0.056 BTC in it, worth about $7,015 at the previous high of $124,493, or $4,170 after electricity. Added to the $3,163 already banked, that takes the machine past its $6,140 landed cost before the halving, on the assumption behind every forward projection.
A buyer today pays $1,794 for the same machine, a first-year return of about 36% at Argentina's 6¢, and it has the best entry price it has ever had. Our review of the S21 Pro covers the purchase. For the owner of the original, the lesson of two years is the one in the roof guide: a 15 J/TH machine bought at a settled price keeps earning when hashprice dips, and the figure below ranks what we would put next to it today.
Bought six months after a halving, it has never needed a day off.
- MicroBT Whatsminer M74S+ (332 TH/s) — 12 J/TH, In stock, $40,369 of electricity per bitcoin, 30% year one
- Bitmain Antminer S23 (318 TH/s) — 11 J/TH, Pre-order, $37,005 of electricity per bitcoin, 28% year one
- Bitdeer SealMiner A4 Pro Air (336 TH/s) — 10.9 J/TH, Sold out, $36,664 of electricity per bitcoin, 44% year one
Sources and further reading
- Bitmain Launches Antminer S21 Pro, Its Most Advanced Bitcoin Miner — Bitcoin Magazine, 29 Mar 2024
- Antminer S21 family hashboard repair: domain map and parts — D-Central, 2026
Which machines this covers
The other side of this machine
Bitmain Antminer S21 Pro review — The best purchase on our floor: 234 TH/s at 15 J/TH at a settled price — a machine that covers its own hardware by the next halving and keeps clearing at our rates well beyond it.
Disclosure
Firsthand Bitcoin sells and hosts mining hardware, including this machine. No manufacturer, distributor or affiliate programme paid for or reviewed this page and we take no commission on the links above. Historical figures are computed from daily bitcoin price and network hashprice, each day valued at its own prices. Nothing here is investment advice.