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Machine review · Oct 4, 2026 · 4 min read

Bitdeer SealMiner A3 Hyd review: a sound 13.5 J/TH machine, and the better-value one beside it

Bitdeer's 500 TH/s water-cooled machine runs at 13.5 J/TH in a 2U chassis, on silicon the company designs itself. It clears its power at both of our rates. Here is where it fits among the water-cooled machines in stock, and which ones to weigh it against.

Firsthand card: "Bitdeer SealMiner A3 Hyd review", the machine's store photo beside its 13.5 J/TH efficiency, 500 TH/s, hydro-cooled

Bitdeer SealMiner A3 Hyd (500 TH/s)

The bottom line

The SealMiner A3 Hyd is the standard water-cooled model of Bitdeer's third generation: 500 TH/s from 6,750 W, 13.5 J/TH, in a 2U rack chassis. At our UAE site it makes a bitcoin for about $44,000 of electricity and returns roughly 38% in its first year at today's price. At Nigeria's rate, the same machine makes a coin for about $28,600.

Bought the week we first held a price for it, in April 2026, it has mined and kept 0.0445 BTC for $1,941 of power: $1,821 of cashflow against a $8,658 landed cost, which is 21% of the hardware in 186 days. Between now and the 2028 halving it has another 0.134 BTC in it, worth about $16,660 with bitcoin back at its previous high: roughly 2.1× its hardware by the halving, and still running after it.

What you are buying is a mature efficiency class, a maker with its own fleet behind the design, and a price that has sat still. What you are not buying is the best value in the class: the S21e XP Hyd 3U is a little more efficient at $9.24 a terahash against this machine's $13.65, and returns about 56% in year one to this machine's 38%. For the cheapest coin, the S23 generation is a step up.

Scores

CriterionScoreWhy
Cashflow6/10Makes a bitcoin for about $44,000 of electricity at 6¢ and returns roughly 38% in year one at today's price. Sound, and well below the 56% of the S21e XP Hyd 3U.
Longevity6/1013.5 J/TH keeps it above the line at 6¢ through the halving, by a small margin, and well above it at 3.9¢. The S23 generation buys distance beyond that; this machine buys the halving and not much more at 6¢.
Efficiency6/10Good for last year and middling for this one: the S23 generation runs 9.5 to 10 J/TH on the same kind of loop, and the S21e XP Hyd 3U runs 13.0.
Quality control5/10Scored as unknown rather than as good. We found no operator reports of this machine's boards in the field, which is what a machine that has been on sale for about a year looks like.
Serviceability6/10Bitdeer's warranty runs 365 days from shipment. Hosted in the UAE, the Bitmain warranty centre is near the site but this is not a Bitmain machine, so repairs follow Bitdeer's own route.

Weighted on what an owner gets back per dollar over the next four years, with efficiency and the 2028 halving next. It clears its power comfortably at both rates, which keeps it above the middle, and a higher price per terahash than the machine at the same efficiency class holds it below the top.

Buy it if

Walk away if

What Bitdeer shipped

Bitdeer announced the A3 range on 16 September 2025 as its third generation of SEALMINER machines, built on what the release calls "self-developed SEAL series of mining chips". Four models launched together: the A3 Pro Hydro at 660 TH/s and 12.5 J/TH, the A3 Pro Air at 290 TH/s and 12.5 J/TH, the A3 Hydro at 500 TH/s and 13.5 J/TH, and the A3 Air at 260 TH/s and 14 J/TH.

The A3 Hydro is the standard water-cooled model. Bitdeer's own listing gives it 500 TH/s from 6,750 W at 13.5 J/TH, and the launch release puts the power between 6,210 and 7,290 W, the tolerance on a 13.5 J/TH machine. The Pro model above it is the one we reviewed first: the A3 Pro Hyd review covers the 12.5 J/TH step.

Chart: Coins kept since the first week we held a price for it, the electricity that made them, and where it lands by the 2028 halving.

A 2U box that takes hot water

The chassis is a 2U rack unit, 482 mm wide and 665 mm deep, weighing 20.5 kg, according to D-Central's specification sheet, which matches the weight in our own record. It takes three-phase 380 to 480 V and a coolant inlet between 20 °C and 55 °C. That is five degrees more headroom at the hot end than the 50 °C the S21e XP Hyd 3U allows.

In the Gulf that matters in the afternoon. A dry cooler delivers its warmest water exactly when the air outside is hottest, and a machine with a wider inlet range spends fewer hours near its limit. It is a small point in the machine's favour, and an honest one.

Like any rack unit it draws the load of several free-standing machines from one position on the loop, which is why we count units like this by positions of infrastructure, not by the box. Racked in the UAE, the plant it needs already exists.

A coolant inlet of up to 55 °C: the machine keeps hashing when the dry coolers deliver their warmest water.

Priced above the machine beside it

The first price we hold for it, in April 2026, was $6,825. It is $13.65 a terahash today, $6,825 for the unit, for the same 500 TH/s at the same 13.5 J/TH. The price has barely moved in the months we have held it.

That is the number to read against its neighbours. The S21e XP Hyd 3U is $9.24 a terahash at 13.0 J/TH, and its coins cost about $41,900 of electricity against this machine's $44,000. It asks more of the room: three-phase power, a coolant loop and racks rated for a 43 kg unit. For an owner who has that room, the 3U is the better-value way into this efficiency class.

What the A3 Hyd offers in exchange is a smaller step. At 500 TH/s a unit is 360 TH/s smaller than the 3U's 860, so it suits owners who add hashrate in modest steps.

Chart: What it has cost from the first price we hold. A flat line, in a class where most machines settle.

What a coin costs it

At 6¢ in the UAE it makes a bitcoin for about $44,000 of electricity today. At Nigeria's 3.9¢ the same machine would make one for about $28,600, and it would cross there once, later in its life, when the trailing year says cheap power pays better. Water-cooled machines start in the UAE, where the loop, the 99% uptime and the warranty centre are.

The S23 Hyd, a generation ahead at 9.5 J/TH, makes a coin for about $31,200 in the same room. The S23e Hyd 2U, at 10 J/TH, makes one for about $32,400. A coin costs this machine about a third more electricity than either, or more.

Over its run so far, since April 2026, electricity has averaged $43,600 a coin. That is a short lifetime average; the figure to plan on is today's.

Chart: One bought today at today's price and racked in the UAE: year one at today's difficulty, and what it returns by the April 2028 halving with bitcoin back at its previous high.

Does 13.5 J/TH last through the halving?

A machine's line is the hashprice at which it stops covering its own power. At 13.5 J/TH a petahash uses 324 kWh a day. That is $19.44 at 6¢ and $12.64 at 3.9¢.

Network hashprice was $40.38 per petahash per day on 3 October on our hashprice chart. The 2028 halving cuts the coins a petahash earns in half at an unchanged price and difficulty, which would put it near $20.19. That is above the line at 6¢ by 75 cents and well above it at 3.9¢.

This is today's conditions held flat, not a forecast. It says the A3 Hyd is not at risk of being switched off at the halving at either rate, and that at 6¢ it carries to the halving with little to spare. The guide to efficiency and halvings has the long version.

Chart: Network hashprice over the last year. Half of today's level is the case this machine is built to clear. Open the chart

A maker that mines with its own machines

Bitdeer mines at scale itself, and the A3 is the machine it is putting into its own halls. Its January 2026 production update lists 8.7 EH/s of A3 machines cumulatively deployed, with another 3.8 EH/s in final assembly. The same update puts the company's own self-mining hashrate at 63.2 EH/s, so the design sits inside a fleet its maker runs every day.

What is not known yet is how the boards behave over years. The machine has been on sale since late 2025, and we looked for operator reports of its boards and found none we could stand behind, so there are none in this review. We score reliability as unknown, not as good.

What a fault costs you here

Every machine on this site develops faults eventually. Bitdeer's warranty runs 365 days from shipment. Hosted with us, a fault is a repair queue and not a shipment from your own address, and it is a line item, not a catastrophe.

Chart: Scored on what costs an owner money over a four-year life, not on spec-sheet numbers.

Our two cents

The A3 Hyd is a sound machine for someone who specifically wants Bitdeer's design, wants to buy 500 TH/s at a time and has the loop to take it. At 13.5 J/TH it clears its power at both our rates and carries to the halving.

For most buyers of water-cooled hashrate the better answer sits beside it. The S21e XP Hyd 3U gets more first-year return from the money, and the S23 generation makes the cheaper coin if you are buying for the years after the halving. Both are in the figure below, ranked on cost per coin and then year-one return.

What beats it on cost per coin and on first-year return, in stock today.

Sources and further reading

Which machines this covers

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.