MicroBT's WhatsMiner line is the main rival to Bitmain's Antminer, and in 2026 it's where a lot of the best terahash-per-dollar value sits. But the naming is a maze — M50, M60, M63, M66, M78, M79, each with S, S+ and S++ variants and air or hydro cooling. This guide cuts through it, compares the three models most people actually shortlist (M66S, M78S, M63S), and tells you which to buy for your power situation.
WhatsMiner naming, decoded
The number after the "M" is the chip generation: M5x is the older 5nm gen (efficient-ish, cheap), M6x is the current mainstream (M60/M63/M66), and M7x is the newest, most efficient gen (M70/M78/M79). The "S" means the high-performance bin, and the S → S+ → S++ ladder marks successive tuned revisions that raise hashrate and improve efficiency on the same silicon. Air-cooled units are plug-and-play; hydro units need a water loop and three-phase power.
WhatsMiner M66S vs M78S vs M63S: specs head-to-head
| Model | Hashrate | Power | Efficiency | Cooling | Price |
|---|---|---|---|---|---|
| M66S | 298 TH/s | 5,513 W | 18.5 J/TH | Air | $3,999 |
| M78S | 472 TH/s | 6,550 W | 13.9 J/TH | Hydro/air | $6,230 |
| M63S | 390 TH/s | 7,215 W | 18.5 J/TH | Hydro | $3,944 |
| M50S | 128 TH/s | 3,276 W | 25.6 J/TH | Air | $960 |
| M79S | 1.35 PH/s | 20,000 W | 14.8 J/TH | Hydro | $8,520 |
The standout is the M78S at 13.9 J/TH — MicroBT's newest M70-gen silicon and the only model here that gets close to breakeven on home power. The flagship M79S produces the most raw hashrate (1.35 PH in one box) but at 14.8 J/TH it's about scale, not efficiency.
Bitcoin mining economics right now (June 2026)
As of mid-June 2026, Bitcoin sits around $64,000–66,000, network difficulty recently fell about 10% to its lowest level since July 2025, and hashprice has recovered to roughly $0.033 per TH per day. That backdrop rewards efficient machines and punishes power-hungry ones.
Profitability: hosted ($0.02) vs home ($0.10)
Assumptions: hashprice ≈ $0.0335/TH/day, 100% uptime, 30-day month, electricity only (no hardware amortisation). These are estimates that change daily.
| Model | Gross/month | Net/month @ $0.02 | Net/month @ $0.10 |
|---|---|---|---|
| M66S (298T) | ~$303 | ≈ +$223 | ≈ −$99 |
| M78S (472T) | ~$481 | ≈ +$385 | ≈ breakeven |
| M63S (390T) | ~$397 | ≈ +$292 | ≈ −$129 |
At home power only the efficient M78S stays near breakeven; the M66S and M63S lose money. At hosted power all three are solidly profitable. That single table is the strongest argument for either buying the most efficient machine you can, or running a cheaper one in a low-cost hosting facility.
Air-cooled vs hydro: which setup fits you
Air-cooled units like the M66S and M50S are plug-and-play and ideal for home or small deployments. Hydro units like the M63S and M79S deliver more hashrate and better density but need water cooling and three-phase power — perfect for hosting farms, impractical in a spare room.
Which WhatsMiner should you buy?
- Best value air-cooled: M66S ($3,999) — proven, simple to run, strong at hosted power.
- Best efficiency / hosting pick: M78S ($6,230) — newest silicon, lowest J/TH, the longevity choice.
- High terahash at mid price: M63S ($3,944) — most TH-per-dollar of the hydro units.
- Cheapest entry: M50S ($960) — budget on-ramp, but 25.6 J/TH means cheap power only.
WhatsMiner vs Antminer S21
Bitmain's newest hydro Antminers currently lead on raw efficiency (the S21 XP Hyd is near 12 J/TH), while WhatsMiner counters with strong value on the M63S and M66S and closes the efficiency gap with the M78S. For value air-cooled mining the M66S and the Antminer S21 are closely matched; for bleeding-edge efficiency Bitmain edges ahead; for hosted terahash-per-dollar, WhatsMiner is very compelling.
Run your WhatsMiner where power is cheap
Hydro machines like the M63S and M78S shine in a real facility. Host with us from $0.018/kWh — we handle cooling, uptime and maintenance while you keep every satoshi.
Ready to choose? Compare live stock and prices on the miners page, or read our 2026 mining hardware guide for the wider picture.