Guide · Oct 21, 2026 · 5 min read
What XP, Pro, S++ and Hyd mean in a bitcoin miner's name
XP, Pro, S++ and Hyd are not decoration. Inside one maker's range they mark a step up in efficiency, and a word or a digit says how the machine is cooled. Here is how to read a name in three steps, and where the pattern breaks.
A miner's name is a code you can read
Open any store and the names look like passwords: Antminer S21 XP Hyd, Whatsminer M63S++, Avalon A15 Pro. They are not random. Each name tells you three things before you open the spec sheet: how new the machine is, how efficient it is for its generation, and how it is cooled.
No maker publishes a key to its names. What follows is the pattern in the machines we list, checked against their efficiency figures, so you can use it for a first guess. The guess always gets confirmed on the spec sheet, and the number to confirm is J/TH: joules of electricity for each terahash of work. Lower is better.
The number is the generation
The number is the model generation, and a higher number is newer. Bitmain's plain air-cooled Antminer uses 17.5 J/TH in the S21 and 11 J/TH in the S23. MicroBT's plain Whatsminer M60 uses 19.9 J/TH and the M70 about 14.5.
A newer generation does the same work for less electricity. That is why efficiency decides how many halvings a machine survives: the machine with the lower figure still pays its power bill when the coins per terahash halve.
The letters are a ladder inside one generation
Within a generation, extra letters and plus signs mean a step up in efficiency. In Bitmain's S21 air range the plain S21 is 17.5 J/TH, the S21+ is 16.5, the S21 Pro is 15 and the S21 XP is 13.5. In MicroBT's M6 range the plain machine is 19.9, the S is 18 to 18.5, the S+ is 17 and the S++ is 15 to 15.5.
Each rung spends less electricity on the same work. At the same power price, an S21 XP spends about 77% of what a plain S21 spends on every terahash, since 13.5 ÷ 17.5 is 0.77. Put another way, the S21 XP makes each coin for about a quarter less electricity than the plain S21.
Inside one maker's range, every extra letter is usually a step up in efficiency.
| Antminer, air-cooled | J/TH |
|---|---|
| S21 | 17.5 |
| S21+ | 16.5 |
| S21 Pro | 15 |
| S21 XP | 13.5 |
The ladder is also a timeline
A higher rung is usually a later launch, not only a better chip. MicroBT introduced the M60, M63 and M66 in October 2023, and Bitcoin Magazine reported their efficiency at 18.5 and 19.9 J/TH. Nine months later, in July 2024, the same magazine covered the M6XS+ series, with the M66S+ at 17 J/TH. The S++ models followed in December 2024, and Forklog quoted the press release: "all three ASIC miners offer an energy consumption rate of 15.5 J/TH".
So the ladder tells you something about age as well as efficiency. A plain M6 machine is the oldest design in its range, and an S++ the newest. Inside a generation, a later rung is a better machine, and it is also one with less time in the field behind it.
The cooling is in the name, one way or another
Bitmain and Bitdeer spell it out. Hyd means water-cooled and Immersion means the machine runs submerged in a tank; Bitmain's plain names are air-cooled, and Bitdeer writes Air. MicroBT puts it in a digit. When it launched the series, Bitcoin Magazine reported the M60 and M60S as air-cooled, the M63 and M63S as hydro-cooled and the M66 and M66S as immersion-cooled. The models we list follow the same digits: an M61S+ is air-cooled, an M65S+ water-cooled and an M66S+ immersion-cooled.
Cooling often moves efficiency a little. The S21 XP is 13.5 J/TH in air and 12 as the S21 XP Hyd, and the S21+ is 16.5 against 15 for the S21+ Hyd. Not always: Bitdeer's A2 Pro Air and A2 Pro Hyd are both about 14.9, and MicroBT's S+ machines are 17 whichever way they are cooled.
Cooling also decides where a machine can live. Water-cooled and immersion machines need a plant built for them, which is why we start them in the UAE and start air-cooled machines in Argentina. The guide to cooling says what each kind needs.
Another maker's ladder can run differently
The ladder is a habit, not a rule. Canaan's Avalon A15 is 18.8 J/TH, the A15 Pro is 16.6 and the A15 Pro+ is 15.5, which reads like Bitmain's. But the A15XP is 17.8, less efficient than the A15 Pro. At Bitmain, XP is the top of the S21 ladder. At Canaan it is not.
Bitdeer's SealMiner names read the way Bitmain's do: the A3 Air is 14 J/TH and the A3 Pro Air 12.5. The lesson is to learn each maker's ladder from its own figures and never carry one maker's meaning of a suffix to another.
| Avalon, air-cooled | J/TH |
|---|---|
| A15 | 18.8 |
| A15XP | 17.8 |
| A15 Pro | 16.6 |
| A15 Pro+ | 15.5 |
2U, 3U and the speed numbers
Some names end in a size. U is a rack unit, the height of a box in a standard rack: 44.45 mm to a unit. Our Antminer S21e XP Hyd is 430 TH/s at 13 J/TH, and its 3U version is 860 TH/s at the same 13 J/TH. The S23 Hyd is 563 to 580 TH/s and the S23 Hyd 3U 1,160 TH/s, both at 9.5 J/TH. The size letters change how much work one box does, not how efficiently it does it.
A number such as 270 or 473 after a name is the hashrate of one particular bin, and the same name often comes in several. Why the same miner comes in different hashrates explains which one to buy.
What a name does not tell you
A name says nothing about the price, and the price of the box is only part of what you pay: the guide to what a miner costs all-in shows what sits on top.
It says nothing about how reliable the boards are, either. Every machine develops faults, and what matters is what a fault costs where the machine lives: a failed hashboard is a line item, not a catastrophe. And it does not say which hashrate bin you are getting, which is a question for the spec sheet and the listing.
Reading a name in three steps
Step one, the number: it is the generation, so higher is newer. Step two, the letters: they are a rung on that maker's efficiency ladder, usually more letters for lower J/TH. Step three, the cooling: a word, or a digit for MicroBT, and it tells you what room the machine needs.
Take the Antminer S21 XP Hyd. S21 is the generation, XP is the top rung of the S21 ladder, and Hyd means water-cooled. The store lists it at 12 J/TH. Take the Whatsminer M63S++: M6 is the generation, the 3 says water, and S++ is the top rung at 15 to 15.5 J/TH. Try it on three names from the store before you move on, and check each guess against the J/TH on its page. After three, the pattern comes quickly and you can shortlist a whole page of machines at a glance.
Then open the spec sheet and read the J/TH, because that is the number you are buying. It decides how many coins a machine keeps after every halving, and what a coin costs it to make. A name gets you to the right shelf; what a miner costs all-in tells you what to pay on it.
Sources and further reading
- MicroBT Unveils Highly Anticipated WhatsMiner M60 Series At Blockchain Life 2023 In Dubai — Bitcoin Magazine, 24 Oct 2023
- MicroBT Unveils New WhatsMiner M6XS+ Series At Bitcoin 2024 Conference — Bitcoin Magazine, 26 Jul 2024
- MicroBT unveils new line of bitcoin miners — Forklog, 9 Dec 2024
- 19-inch rack — Wikipedia, 2026
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.