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Machine review · Nov 6, 2026 · 5 min read

Whatsminer M65S review: 18.5 J/TH in the water loop, and Nigeria is where it pays

MicroBT's M65S is a hydro-cooled Whatsminer: 404 TH/s from 7,474 W, 18.5 J/TH. It costs less per terahash than the M63S that shares its efficiency and it earns its keep on Nigerian power, but the M65S+ one step up makes a coin for less.

Firsthand card: "Whatsminer M65S", review, 18.5 J/TH, 404 TH/s hydro-cooled, with the machine itself on a dark background

MicroBT Whatsminer M65S (404 TH/s)

The bottom line

The M65S is MicroBT's hydro-cooled Whatsminer at 18.5 J/TH: 404 TH/s from 7,474 W in the unit we list. Hydro machines start in the UAE, at 6¢, where it makes a bitcoin for about $67,300 of electricity and returns roughly 12% in its first year at today's price. At Nigeria's 3.9¢ the same machine makes one for about $43,800 and returns 31%.

Bought once its price settled, in July 2026, it has mined and kept 0.0240 BTC for $1,429 of power: $503 of cashflow against a $4,441 landed cost, 11% of the box in 124 days. Between now and the 2028 halving it has another 0.067 BTC in it, worth about $8,380 with bitcoin back at its previous high of $124,493: roughly 2.0× its hardware by the halving, still running afterwards.

What you are buying is a low price per terahash at this efficiency: $6.20 against $7.14 for the 400 TH/s M63S at the same 18.5 J/TH. What you are not buying is the cheapest coin. The M65S+ at 17 J/TH makes one for about $62,000 in the UAE and returns 19% in year one, for $6.72 a terahash.

Scores

CriterionScoreWhy
Cashflow4.5/10Makes a bitcoin for about $67,300 of electricity at 6¢ and $43,800 at 3.9¢, returning 12% and 31% in year one at today's price. It has covered 11% of its hardware so far and is on track for about 2.0× by the 2028 halving.
Longevity3.5/10At 18.5 J/TH its line is $26.64 a petahash a day at 6¢ and $17.32 at 3.9¢, against a hashprice of $32.22 on 6 November. Half of that, the flat-conditions picture after the halving, is $16.11: under both lines, and about $1.20 under Nigeria's.
Efficiency4/10Low among the hydro machines we stock: the M65S+ runs 17 J/TH, the S21e XP Hyd 13 and the S21j XP Hyd 12.
Quality control5/10Scored as unknown rather than as good. We found no operator reports of its boards in the field that we could cite, so there is no record to score.
Serviceability6/10Hydro, so it lives in the UAE to start, where the manufacturer's warranty centre is close to the facility and an in-warranty board goes direct.

Cashflow and longevity carry the most weight, and both lean on cheap power: the M65S works at 3.9¢ and is thin at 6¢.

Buy it if

Walk away if

What MicroBT shipped

The M65S is a water-cooled Whatsminer from MicroBT's M6X range. MicroBT's product manual, dated December 2024, gives it 18.5 J/T within 5%, a hashrate of 370 to 400 TH/s within 10%, a weight of 27.5 kg and a body of 86 by 482.6 by 663 mm with the handle, drawing 10 kW from a 380 to 480 V supply. Outlet water can reach 80°C, with inlet water at 30 to 60°C in normal mode.

The units we list are 404 TH/s from 7,474 W, with smaller bins at 402, 400 and 394 TH/s, all at 18.5 J/TH. Those are our store record; where the manual gives a range we use the record. It sits one step below the M65S+ at 17 J/TH and shares its efficiency with the M63S.

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

Its entry price is lower than in the spring

The first price we hold for the 404 TH/s unit, on 11 March 2026, was $7.14 a terahash, $2,885 a unit. It rose to about $8.09 through the spring, was $7.77 in July, dropped to $6.09 on 5 August and has held at $6.20 since 10 August: $2,503 today, $6.20 a terahash, for the same 404 TH/s at the same 18.5 J/TH.

A purchase after the price settled, in July 2026, cost $3,182. This is close to the best entry price we have held for the machine, and its hashrate is the same as it was in March. In the water loop it is $6.20 a terahash against $7.14 for the 400 TH/s M63S at the same efficiency, and below the $6.72 of the M65S+.

Chart: What the 404 TH/s unit has cost since the first price we hold for it, in March 2026.

What a coin costs it

In the UAE, at 6¢, the M65S makes a bitcoin for about $67,300 of electricity today, against a bitcoin price of $75,826: almost nine-tenths of what a coin sells for. At Nigeria's 3.9¢ it is about $43,800.

In its first year the M65S returns about 12% in the UAE and 31% in Nigeria at today's price. The M65S+ returns 19% in the UAE for $2,715 a unit, and the S21e XP Hyd 33% on $3,793: more outlay, turned into a much cheaper coin, about $47,700 in the UAE.

Over its run since July 2026, electricity has averaged about $59,500 a coin. That is a lifetime average over 124 days; 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 2028 halving.

Where the halving puts it

A machine's line is the hashprice at which it stops covering its own power. At 18.5 J/TH a petahash uses 444 kWh a day: $26.64 at 6¢ and $17.32 at 3.9¢. On our hashprice chart, network hashprice was $32.22 a petahash a day on 6 November, and the lowest reading of the past year was $27.74 on 6 June 2026. The M65S line at 6¢ sat $1.10 under last June's trough.

The 2028 halving halves the coins a petahash earns. At today's price and difficulty that puts hashprice near $16.11, under the line at 6¢ and about $1.20 under it at Nigeria's 3.9¢. That is today's conditions held flat, not a forecast: it is why every projection we publish assumes the old high returns, and why a machine at this efficiency belongs on the cheapest power we have.

The guide to efficiency and halvings shows where the line sits at every J/TH. At 13 J/TH the S21e XP Hyd's line is $18.72 at 6¢ and $12.17 at 3.9¢, and the second sits under half of today's hashprice.

Chart: Network hashprice per petahash per day. The M65S needs about $27 of it at 6¢ and $17 at Nigeria's 3.9¢; halving today's reading puts it near $16. Open the chart

What a fault costs you here

We looked for operator threads and repair write-ups on the M65S and found nothing specific to it that we could stand behind, so the reliability score is unknown rather than good or bad. A quality score needs a record we can cite, and this one has none.

What a fault costs is the part that matters. Hosted with us in the UAE, the manufacturer's warranty centre is close to the facility, so an in-warranty unit goes direct: a failed hashboard is a line item, not a catastrophe. A hydro machine is built for a water loop and is serviced where the plant already exists, which is why we rack it there to start.

Chart: Scored on what costs an owner money over a four-year life. Reliability is scored as unknown.

Our two cents

The M65S is a plain hydro machine at a low entry price, and it earns its keep where power is cheapest. At 3.9¢ it makes a coin for $43,800, about a third under the UAE figure, and it is a low-outlay way into 18.5 J/TH hashrate. At 6¢ it clears its power with less room than the M65S+ next to it.

Most buyers should look one step up. The M65S+ costs $2,715 for the same 404 TH/s and makes a coin for about $62,000 against $67,300 here, and the figure below ranks everything that beats this machine on cost per coin and then year-one return, in stock today. A coin that costs less to make is a coin you keep more of.

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.