What is a Bitcoin mining machine?
Definition ¡ ASIC miner
A machine built around chips that can only do one thing: compute Bitcoinâs double SHA-256 hash. Giving up everything else is what makes it so fast and so efficient.
Inside an air-cooled miner
pull cool air in
Hashboard 1
Hashboard 2
Hashboard 3
Control board
Runs the firmware, talks to the pool over Ethernet
Power supply
Turns mains power into what the chips need
The pool sends the machine work, the chips hash it as fast as they can, and the control board reports back any result good enough to count. The rest of the setup, like power, cooling and the pool account, is covered in what a mining rig is. Thousands of machines together make a mining farm. New to all of this? Start with the complete guide to Bitcoin mining.
Why canât you mine Bitcoin with a GPU any more?
Graphics cards were the best Bitcoin miners in the early 2010s. Then ASICs arrived, and the gap is now so big that the graphics card barely shows up on the chart.
How much hashing one joule of electricity buys
Thatâs roughly 37,000 times more work for the same power. The catch: an ASIC canât do anything else. When it stops paying for Bitcoin, you canât turn it into a gaming or AI machine.
Which specs matter when comparing mining machines?
Hereâs a current air-cooled model, the Antminer S21 XP, as its spec sheet lists it:
270 TH/s
Hashrate
Hashes per second. Decides your share of the network, and so your revenue.
13.5 J/TH
Efficiency
Energy per trillion hashes. The most important number on the sheet.
3,645 W
Power draw
Around the clock. This is your electricity bill and the circuit you need.
76 dBA
Noise
At full fan speed. Think vacuum cleaner that never switches off.
220 to 277 V
Input power
Single phase, up to 20 A. Most normal wall sockets canât supply this.
â20 to 45 °C
Operating range
Plus 10 to 90% humidity, no condensation. Dust cuts airflow.
Manufacturers publish typical figures. Bitmain notes real hashrate can vary by Âą3% and power by Âą5%. So every model number on this page is manufacturer-rated, not something we measured.
How much have mining machines improved?
Energy per terahash, oldest to newest (lower is better)
The S9 needed about ten times more energy for the same work as todayâs best machines. The fleet actually running lags behind the newest models, though. Cambridgeâs 2025 industry survey put the average at about 28.2 J/TH in June 2024, and found Bitmain alone held about 82% of the hardware market.
| Model | Cooling | Hashrate | Power | J/TH |
|---|---|---|---|---|
| Antminer S9 | Air | 14 TH/s | 1,375 W | 98.2* |
| Antminer S19j XP | Air | 151 TH/s | 3,247 W | 21.5 |
| WhatsMiner M60S | Air | 188 TH/s | 3,478 W | 18.5 |
| Antminer S21 | Air | 200 TH/s | 3,500 W | 17.5 |
| Antminer S21 XP | Air | 270 TH/s | 3,645 W | 13.5 |
| Antminer S21 XP Imm. | Immersion | 300 TH/s | 4,050 W | 13.5 |
| Antminer S21 XP Hyd. | Hydro | 473 TH/s | 5,676 W | 12 |
| Antminer S23 Hyd. | Hydro | 580 TH/s | 5,510 W | 9.5 |
At what electricity price does a machine stop paying?
Miners measure revenue as hashprice: what 1 TH/s is expected to earn in a day. It moves with the network hashrate, the block reward and the bitcoin price.
Right now 1 TH/s is expected to earn 0.0000004515BTC a day, about $0.0380. Thatâs a live estimate, updated hourly.
$0.0380
Hashprice, USD per TH/s/day
live estimate
$84,175
BTC price
live
1003 EH/s
Network hashrate
live
3.145 BTC
Block reward
incl. average fees
Hereâs the useful bit. Divide hashprice by a machineâs energy use and you get the electricity price where it stops earning more than it costs. It only depends on J/TH. How big or expensive the machine is doesnât change it.
Break-even electricity price, by efficiency
This is why old machines get unplugged even when they still work. Their break-even price drops below what anyone pays for power. And since the network tends to grow, and each halving cuts the block subsidy in half, every machine earns a bit less bitcoin each year. Try your own numbers in the mining profit calculator.
Air, hydro or immersion: which cooling?
Nearly every watt a miner uses turns into heat. The same S21 XP chips come in three versions, and the cooling changes a lot:
270 TH/s
Air (S21 XP)
Fans push air through the boards. Cheapest and simplest, but loud and sensitive to dust and heat.
300 TH/s
Immersion (S21 XP Imm.)
Boards sit in a tank of non-conductive fluid. Quiet and even, but tanks and fluid cost extra.
473 TH/s
Hydro (S21 XP Hyd.)
Coolant runs over the chips and out to a cooler. Denser and quieter, needs plumbing and often three-phase power.
Liquid cooling makes the most sense when many machines share the pumps, which is why you mostly see it in farms. At home, noise is usually the first problem. The home checklist covers it.
How long does a machine last, and what is it worth used?
5+ years
Possible working life
Cambridge example, with cheap power
86.9%
Retired hardware reused or recycled
Cambridge survey, late 2024
1 year
Typical warranty
Bitmain S21 XP, MicroBT M60S
82%
Bitmainâs market share
Cambridge survey
A machine can keep hashing for years. Fans and power supplies are the usual things to fail, and both can be replaced. What really ends its life is money: once its break-even price drops below your tariff, itâs cheaper to switch it off. Thatâs also why used machines still sell. A unit that loses money on a household tariff can still earn somewhere with cheaper power. Prices for used units fall with each new generation and each halving.
One thing to know before flashing custom firmware: MicroBTâs warranty excludes damage from overclocking and unofficial software.
How do you buy a mining machine without getting scammed?
Mining hardware is expensive, ships internationally and is hard for a beginner to check. Scammers love that.
Good signs
- Sold by the manufacturer, or a reseller the manufacturer lists as authorised
- For used units: you see it running and the hashrate shows up on the pool, not just its own dashboard
- The serial number on the case matches what the control board reports
- Payment with buyer protection
Walk away if you see
- A price far below the manufacturerâs current list price
- âGuaranteedâ daily profits quoted with the sale
- Crypto or wire transfer to a personal account only
- âHosting includedâ where you never see the machine or its pool account
Also budget for shipping, import duty, spare fans, an electrician and pool fees.
Should you buy a machine or use an app?
Theyâre different things, so it depends on what you want.
| Your own machine | CloudMineCrypto | |
|---|---|---|
| You get | The hardware, mining for a pool you choose | Mining plans from the free plan, ads, games, offers and daily check-ins, and a BTC balance that grows while they run |
| To start | Thousands of dollars plus electrical work | Free. Paid plans are an optional add-on, and the price is shown before you confirm. |
| Running costs | Electricity, pool fees, repairs | None |
| Rewards | Your real share of blocks, through a pool | Estimated from your planâs hashrate and live network data, using the formula above, plus any boosts |
| Good to know | Power can cost more than it earns, and hardware loses value | Rewards are estimates, change with the network and arenât guaranteed. A plan isnât ownership of, or a dedicated share in, any hardware or pool, and paid plans can earn less than they cost. |
If you want to tinker with real hardware, buy a machine and learn everything, electricity bill included. If you want to mine without the noise, heat and upfront cost, start for free with the free plan, ads, games, offers and daily check-ins, and withdraw to your own wallet, Lightning included. Want more speed later? Add a paid plan. Terms apply, see the reward rules.
Frequently asked questions
What is the difference between an ASIC and a mining rig?
The ASIC is the machine: a box of chips that only compute Bitcoinâs SHA-256 hash. The rig is the whole setup around it, including the power circuit, cooling, network and the pool it mines for.
What does J/TH mean on a Bitcoin miner?
Joules per terahash, the energy a machine needs for a trillion hashes. Lower is better. Electricity is the main running cost, so J/TH decides which machines can still earn more than they burn.
Can I mine Bitcoin with a graphics card?
You can, but it costs far more in electricity than it earns. A modern ASIC does tens of thousands of times more work per unit of energy than a graphics card.
How loud is a Bitcoin mining machine?
Air-cooled ones are very loud. Bitmain rates the Antminer S21 XP at 76 dBA with its fans at full speed. Hydro and immersion models are much quieter but need pumps and plumbing.
How long do ASIC miners last?
With good cooling and clean power they can run five years or more. They stop being useful earlier if electricity costs more than they earn, which gets more likely as the network grows and after each halving.
Is it safe to buy a used ASIC miner?
It can be. See it running, check its hashrate on the pool rather than its own dashboard, match the serial number, and pay in a way that protects you. Be careful with prices far below the market.
Does a CloudMineCrypto plan mean I own a machine?
No, and you donât need one. You mine for free with the free plan, ads, games, offers and daily check-ins, and the app works out your estimated rewards from each planâs hashrate and live network data. Paid plans are an optional add-on. A plan doesnât give you ownership of, or a dedicated share in, any specific hardware or pool.
Sources and further reading
- Antminer S21 XP specifications ¡ Bitmain (manufacturer)
- Bitcoin miner catalogue (S19, S21 and S23 families) ¡ Bitmain (manufacturer)
- WhatsMiner M60S specifications ¡ MicroBT (manufacturer)
- Mining hardware comparison (Antminer S9 and earlier ASICs) ¡ Bitcoin Wiki
- Non-specialized hardware comparison (CPU and GPU hashrates) ¡ Bitcoin Wiki
- Cambridge Digital Mining Industry Report (April 2025) ¡ Cambridge Centre for Alternative Finance
- Mining guide: solo and pool mining ¡ Bitcoin developer documentation
Live figures on this page (network hashrate, block reward, BTC price) come from the CloudMineCrypto API, refreshed hourly, and are labelled where they appear. This guide is educational and not financial advice. CloudMineCrypto is not an investment product; rewards in the app are estimates and arenât guaranteed.
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