Whatsminer M60S vs Antminer S21: Efficiency, Heat and Running Cost in the UAE

On the manufacturers’ published figures, the Whatsminer M60S vs Antminer S21 gap is one generation and one J/TH: the M60S runs at 18.5 J/TH and the base S21 at 17.5 J/TH. The S21 Pro (15 J/TH) and S21 XP (13.5 J/TH) are the Bitmain units a UAE buyer is more likely to be quoted, and they are further ahead on efficiency. For the brand-level picture, see Antminer vs Whatsminer.

For a Gulf buyer, J/TH is only half the decision. MicroBT publishes an operating range that tops out at 35 C ambient for the M60S. Bitmain publishes 45 C for the S21 family. That difference decides where the machine can run in a Dubai summer.

This page shows the power math at DEWA and ADDC rates, so you can rerun it on your own tariff. Both brands are supplied from Dubai, and used units are bench-tested in our Deira workshop. There is no verdict here, because the answer depends on your power and your site.

Which Antminer S21 is the fair comparison?

Bitmain publishes several S21 variants: the base S21, the S21 Pro, the S21 XP, plus hydro and immersion versions. On hashrate and J/TH, the base S21 at 200 TH/s and 17.5 J/TH sits closest to the Whatsminer M60S.

Newer MicroBT models also sit above the M60S, including the M60S+, M60S++, M66S and M70S on MicroBT’s current listing MicroBT shop listing. They are quoted on request. The full Whatsminer range in the UAE is on its own page.

The published specs side by side

MicroBT M60S specification Bitmain S21 specification Bitmain S21 Pro specification Bitmain S21 XP specification

MicroBT lists three M60S hashrate bins, all at 18.5 J/TH, and one power figure. MicroBT lists 18.5 J/TH and 3,478 W for the product; the two figures do not reconcile exactly at 186 TH/s (3,478 ÷ 186 = 18.70 J/TH). Bitmain states a tolerance of ±3% on hashrate and ±5% on power for the S21 Pro and S21 XP. A unit inside those bands is normal.

Bitmain prints its efficiency unit as J/Ksol on these pages; for SHA-256 miners it reads as J/TH. Compare the M60S, S21 Pro and S21 XP pages for what we supply.

Heat: the 35 C question

MicroBT’s published operating range for the M60S stops at 35 C. In the UAE, intake air above 35 C is normal for months of the year in an unconditioned room, a container without cooling, or a warehouse. Bitmain’s published ceiling for the S21 family is 45 C. That is more headroom on paper, and the machine still needs a steady flow of air at that temperature.

What that means by site:

• An unconditioned room or container. The M60S is outside its published range for much of the summer. It needs conditioned air, or it belongs somewhere else.
• A conditioned room. Both fit, as long as the cooling can remove about 3.5 kW of heat per machine, around the clock.
• A hosted rack. The facility controls intake air, so the published ranges matter less to you than the facility’s own cooling.

For sustained high ambient, MicroBT’s answer is hydro: the Whatsminer M63S hydro. For what heat does to an air-cooled machine, see what an overheating Whatsminer does.

What the efficiency gap costs in electricity

Take the M60S’s middle bin of 186 TH/s. Producing those 186 TH/s at each Bitmain unit’s rated efficiency instead saves 186 W for every J/TH of gap. Continuous, that is 186 W x 24 x 30 = 134 kWh a month per J/TH.

The rates used, as published:

• DEWA commercial. DEWA bills commercial premises on the same slab table as residential: 0.230 AED per kWh up to 2,000 kWh a month, 0.280 to 4,000, 0.320 to 6,000, and 0.380 above 6,000. A site running even three miners passes 6,000 kWh a month, so the gap is billed at the top commercial slab, 0.38 AED/kWh, plus a fuel surcharge of 0.060 AED per kWh: 0.44 AED per kWh before 5% VAT DEWA slab tariff, checked October 2026.
• ADDC commercial. 20 fils per kWh, flat. ADDC’s page is titled 2025 but reads “Effective 01/01/2018”, so check the current rate on addc.ae before relying on it ADDC business rates and tariffs.
• A hosting facility. Published UAE hosting rates ranged from about 6 to 8 US cents per kWh in September 2026. That is market context from provider pages, not our price.

DEWA figures are before 5% VAT. ADDC’s page says its published rates include VAT.

Formula
Watts gap = hashrate (TH/s) x J/TH gap
Monthly kWh = watts gap ÷ 1,000 x 24 x 30
Monthly cost = monthly kWh x your marginal rate per kWh (add any surcharge, then VAT)

Use your own bin and your own rate. Then set the monthly power difference against the difference between the two quotes you receive. That is the whole comparison on the power side. The tariffs are explained in more detail in UAE tariffs explained. If facility power is the cheaper route for you, see hosting on facility power.

Build, PSU and the rack

The M60S is the smaller and lighter machine: 430 x 155 x 226 mm and 13.5 kg on MicroBT’s page. The S21 Pro is 450 x 219 x 293 mm and 20 kg net; the S21 XP is 449 x 219 x 293 mm and 18.7 kg net.

At the wall, MicroBT specifies a P221B or P222B PSU on AC 220 to 240 V, fed through an IEC C19 lead rated 16 A or more. Bitmain specifies 220 to 277 V at 20 A for the S21 family. Either way, the C19 lead and the breaker rating are the first things a UAE electrician will ask about, because both machines pull their full load continuously.

Warranty: what each manufacturer publishes

MicroBT’s product page promises a one-year warranty with repair within the warranty scope. Its exclusions include improper installation, unauthorised modification or repair, unofficial accessories or software, parameter changes such as overclocking, use outside the specified power or environment, serial numbers that have been modified or removed, and natural disasters MicroBT M60S after-sales policy.

Bitmain’s warranty-check article says the warranty on new miners outside the 19 series is “generally 180 days”, counted from the official dispatch date Bitmain, Miner Warranty Check. New 19-series units and new PSUs generally get 365 days.

Those are the manufacturers’ terms. What you rely on when you buy from us is our own written warranty, supplied with the quote. To look up a unit’s status by serial number, check the warranty by serial number. For units out of warranty, we offer board-level repair in Dubai.

Whatsminer M60S vs Antminer S21: which one for which buyer

A hosted buyer on facility power. The efficiency gap is paid in every kWh for as long as the machine runs, so over a long horizon it compounds. Both brands fit a hosted rack. On published J/TH, the S21 XP leads.

A buyer with their own commercial site in the UAE. Ambient temperature decides first. With conditioned air, both work. Without it, the S21 family’s higher published ceiling gives more room, or a hydro unit removes the question.

A buyer who wants a simpler air-cooled unit on stock firmware and has conditioned air. That is the M60S case. Run its power cost at your rate against the S21 quotes before you commit.

Haseeb Aslam
Founder, Keep Hashing
Mining since 2021, and working with ASIC hardware since founding Keep Hashing in September 2022.