ASIC miners are chips built only to compute SHA-256 as fast and efficiently as possible. Learn how they replaced CPUs and GPUs and what specs matter.
From laptops to factories
ASIC stands for application-specific integrated circuit: a chip that does one task. Bitcoin ASICs only compute double SHA-256 on block headers, and are millions of times more efficient at it than a general-purpose computer.
What matters in a miner
| Spec | Meaning |
|---|---|
| Hash rate | Hashes per second, in terahashes (TH/s) |
| Efficiency | Joules per terahash (J/TH): lower is better |
| Power | Watts drawn from the wall |
Electricity is the main ongoing cost, so the cheapest power wins. Miners cluster where energy is cheap or would otherwise be wasted.
ASICs and security
Because ASICs are useless for anything else, miners are heavily invested in Bitcoin's success. Attacking the network would destroy the value of their own equipment.
Reading a miner's spec sheet
Comparing two machines
Machine A: 200 TH/s at 3,500 W, which is 17.5 J/TH. Machine B: 120 TH/s at 3,000 W, which is 25 J/TH. Machine A does more work per unit of electricity, so it stays profitable longer as difficulty rises.
Heat and noise
ASICs turn almost all their electricity into heat and are very loud. That's why they live in warehouses, and why some people reuse that heat for homes, greenhouses or water.
Key takeaways
- ASICs are chips designed only for Bitcoin's SHA-256 hashing.
- Efficiency (J/TH) and electricity cost decide profitability.
- Single-purpose hardware ties miners' interests to Bitcoin.
Common questions
Can I mine with my GPU?
Not profitably. GPUs are thousands of times less efficient than ASICs for SHA-256.
Are ASICs only for Bitcoin?
Bitcoin ASICs work for any coin that uses the same SHA-256 proof of work, but nothing else.
How long do ASIC miners last?
Physically several years, but newer, more efficient models often make older ones unprofitable sooner.
Can ASICs mine other coins?
Only coins using the same SHA-256 proof of work.