Home Mining

Bitaxe Gamma Duo: four units, 105 watts, 6.59 TH/s.

READ6 min · UPDATED2026-05-08

Reviewed against primary sources cited at the bottom of this page.

A first-person review of running four Bitaxe Gamma Duo units in parallel, pointed at solo CKpool, in a residential setup. Measured wattage, measured hashrate, setup notes, and the honest math on expected returns. The Bitaxe Gamma Duo is not a profitable miner. That is not the point. This review covers what it actually is and what it actually does.

This page is a first-person review based on hands-on operation, not a sponsored placement. The hardware was purchased at retail. No affiliate relationships with any seller.

THE SHORT VERSION

Four Bitaxe Gamma Duo units running 24/7 produce approximately 6.59 TH/s combined at approximately 105 watts of total wall power. That hashrate is roughly 0.0009% of total network hashrate (at ~700 EH/s). The probability of solo-mining a block per device per year is approximately 1 in 35,000, a lottery ticket, not a paycheck. The reason to run them is education, sovereignty, the heat output (these are excellent space heaters in winter), and the asymmetric chance of winning a block reward. Profitability is not the reason.

What the Bitaxe Gamma Duo actually is

The Bitaxe is an open-source Bitcoin miner designed by Skot. The "Gamma" generation uses two BM1370 ASIC chips per board (hence "Duo"), running at roughly 1.65 TH/s per unit at ~26 watts. The PCB is roughly the size of a Raspberry Pi. The board exposes a web interface for configuration, monitoring, and pool switching verify×DON'T TRUST, VERIFYClaim: Bitaxe Gamma Duo uses 2x BM1370 ASIC chips per board at ~1.65 TH/s and ~26W per unit.Verify at: Bitaxe GitHub ↗Spec depends on firmware tuning and individual chip variance. Confirm against the Bitaxe repo and your own measured values..

Compare to a commercial S21 Pro miner running at ~234 TH/s and ~3,500 watts. The Bitaxe is approximately 140x less hashrate but also approximately 130x less power. The hashrate-per-watt is competitive; the absolute output is intentionally small.

Measured values, four-unit cluster

FOUR-UNIT CLUSTER, RUNNING 24/7 ON SOLO CKPOOL

Per unit: 1.65 TH/s average, 26 watts at the wall
Four-unit total hashrate: ~6.59 TH/s
Four-unit total power: ~105 watts at the wall (including router and Wi-Fi)
Efficiency: ~16 watts per TH/s (J/TH)
Noise: mostly fan noise; with default fans, audible but not disruptive at conversational distance
Heat output: ~105W of dissipated heat, equivalent to a small incandescent bulb running constantly

These figures are measured at the wall (Kill A Watt or equivalent), not estimated. Variance between individual units is small (under 5%) once thermal management stabilizes.

Setup notes

Power delivery

Each Bitaxe requires a 5V/4A power supply via the barrel jack. The community has gone back and forth on whether USB-C PD works; the safer choice is the official-spec power brick. Bad PSUs are the most common cause of hash rate dropping or units rebooting unexpectedly. Four units fit on a standard surge-protected power strip with room to spare.

Network configuration

Each Bitaxe connects to Wi-Fi via its built-in interface. First boot, it broadcasts an AP that you connect to from a phone, then configure your home SSID and pool credentials. After that it pulls work over Stratum. Pool config for solo CKpool:

Pool: solo.ckpool.org:3333
Username: your-bitcoin-payout-address
Password: x (any value)

Solo CKpool means you are not pooling rewards with other miners. If any one of your boards finds a valid block, the full coinbase plus all transaction fees pays to your address. Otherwise, you earn zero. The expected value is the same as joining a normal pool minus pool fees; the variance is enormous.

Cooling and thermal management

Stock heatsink + fan is sufficient at default frequencies (485 MHz on the BM1370). Pushing the frequency above 525 MHz starts pulling more watts without proportional hashrate gain and risks thermal throttling. The default tune is the sweet spot. In a cold room (sub-65°F), you can push slightly higher; in a warm room (75°F+), keep stock.

The lottery math

Probability of solo-mining a block in a year for a 1.65 TH/s miner, given network hashrate of approximately 700 EH/s and 52,560 blocks per year (one per 10 minutes):

SOLO BLOCK PROBABILITY

Your share of hashrate: 1.65 TH/s ÷ 700,000,000 TH/s = 0.00000000236, or 2.36 in a billion.

Blocks per year: ~52,560. Expected blocks per year for one Bitaxe: 52,560 × 0.00000000236 = 0.000124, or approximately 1 in every 8,065 years.

Probability of finding at least one block in a year with one Bitaxe: approximately 0.0124% (1 in ~8,065).

Probability with four units: approximately 0.05% (1 in ~2,000).

If a block hits, the reward at current 3.125 BTC subsidy is approximately $240,000 plus transaction fees. The expected dollar value per year is approximately $120 per Bitaxe (at $77K BTC).

The expected return matches roughly what the cost of electricity is. Solo CKpool has produced individual solo block wins by Bitaxe operators several times in 2024-2025 (a small but non-zero number). Each is genuinely a lottery win.

Why run it

Education. You learn how mining actually works. Stratum protocol, share submission, difficulty, target. The Bitaxe web UI is small enough that the protocol becomes legible.
Sovereignty. You are participating in network security at a tiny but non-zero level. Bitcoin doesn't need your hashrate. You're proving to yourself that participation is possible.
Heat output. 105 watts of constant dissipated heat is meaningful in a small room. In winter you are heating a corner of your house with money the network might give you. The marginal cost of heat is approximately zero if you would have run electric heat anyway.
Lottery. The probability of hitting a block is tiny. The reward if you do is several years' median household income.
It is fascinating to watch. The web dashboard updates every few seconds. You see shares get accepted in real time. There is a tactile, "actually running a node and miner" quality to it that no exchange account replicates.

The reasons not on this list: profit. Anyone running these for profit is mathematically confused.

What goes wrong

PSU failures. The cheap power supplies sometimes die. Symptoms: random reboots, dropped Wi-Fi connection, or one unit just turning off. Buy good PSUs.
Wi-Fi disconnects. The ESP32 onboard chip occasionally loses Wi-Fi and doesn't auto-reconnect on some firmware versions. A reboot brings it back. A periodic ping check can detect and auto-reboot if needed.
Thermal throttle in summer. Stock cooling is fine in conditioned spaces. In an uninsulated garage at 90°F+, the fans can't keep up and the chip clocks down to protect itself.
Pool stratum quirks. Solo CKpool occasionally has connection hiccups. The Bitaxe firmware reconnects automatically; lost shares during the reconnect window are negligible.

Common questions

How much does this cost to run?

Four units at 105 watts is approximately 0.105 kWh per hour. Over a year: 920 kWh. At average US residential electricity rate (~$0.16/kWh): approximately $147/year. Higher in California, lower in Texas. Roughly matches expected mining revenue, with the lottery upside on top.

Should I do solo or pool mining?

Expected value is approximately the same. Pool mining gives a small steady payout (a few sats per day per Bitaxe); solo gives zero almost every day with a lottery upside. The Bitaxe community heavily favors solo because the asymmetric reward is part of the appeal.

Is this profitable?

Expected return roughly equals the electricity cost in moderately-priced US states. Solo upside is real but small. Treat it as a hobby with educational and lottery value, not as an investment.

Can I run more than four units?

Yes. People run dozens. The constraint becomes electrical capacity, network capacity (each unit needs Wi-Fi or wired), and noise. At ten units the room becomes meaningfully warmer and the cumulative fan noise becomes office-loud.

Where to buy?

The Bitaxe is open-hardware; multiple resellers manufacture and sell completed boards. Verify the vendor against the active Bitaxe community discussions before buying because counterfeits exist. The bitaxe.org domain links to current authorized sellers.

Home mining · the broader framework
Running a Bitcoin node · pair the miner with a node
Solo mining calculator · model your specific hash rate
Start9 Server One setup · the node hardware companion
Sparrow wallet · for receiving the block reward if you hit one

Sources

Bitaxe open-hardware project, GitHub repository · github.com/skot/bitaxe
Solo CKpool · solo.ckpool.org
Bitcoin network hashrate (live) · mempool.space
BM1370 ASIC specifications from chip manufacturer; verify against Bitaxe documentation
First-person measurements with calibrated Kill A Watt meter at the wall outlet

Last updated 2026-05-08. Not financial advice. Do your own research.

Subscribe via RSS for new articles.