The Bitaxe Naja Duo is the first Bitaxe built on Bitmain’s 3nm BM1373 ASIC, and it resets the efficiency ceiling for open-source home mining. Released exclusively through Solo Satoshi in August 2026, the Naja Duo (1201 model) produces 4.4 TH/s at 42 watts, with a stock efficiency of 9.5 J/TH.
Efficiency, measured in joules per terahash, is the number that decides what mining actually costs. It is the energy a miner burns to produce one terahash of work: lower means more hashrate per watt, less electricity on the bill, and less heat in the room. Every BM1370-based Bitaxe released between 2024 and 2026 lands between 15 and 18 J/TH at default settings. The Naja Duo cuts that nearly in half in a single generation while doubling per-board hashrate over the previous flagship at identical power draw.
Inside the BM1373: Bitmain’s 3nm S23 Silicon
The BM1373 is Bitmain’s 3nm SHA-256 ASIC from the Antminer S23 generation, rated at roughly 2.5 TH/s per chip at about 10 J/TH. Moving from a 5nm to a 3nm process shrinks each transistor, and smaller transistors switch with less voltage and leak less current. Since a mining chip is billions of transistors flipping nonstop, that per-transistor saving compounds into the largest efficiency gain the SHA-256 world has seen since 2022.
Each BM1373 die is organized into 8 independent hashing domains, separate blocks of cores that can be clocked and measured on their own. One BM1373 matches the throughput of two BM1370 chips, the S21-generation silicon inside the Bitaxe Gamma 602, Gamma Duo 650, and GT 801. Denser chips multiply what the same footprint can do: the Naja Duo keeps the classic single-heatsink, single-fan Bitaxe layout but pushes 4.4 TH/s through it instead of 2.15, with no extra noise, bulk, or cooling complexity. That is how a two-chip board matches the hashrate class of last year’s four-chip designs at roughly half the power.
The pace of that consolidation is worth pausing on. The 2023 Bitaxe Ultra produced about 0.5 TH/s from one chip. The 2024 Gamma 602 reached 1.2 TH/s. The Naja Duo now delivers 4.4 TH/s, a 9x per-board improvement in under three years, with every schematic, board layout, and firmware commit published openly on the bitaxeorg GitHub. Nothing about the design is licensed, locked, or hidden.
Stock Performance and Headroom
Default settings run the BM1373 pair at 327 MHz and 1,000 mV, producing 4.4 TH/s at about 42 W. The tested overclock profile runs 600 MHz at 1,120 mV for 8 TH/s at roughly 92 W, or 11.5 J/TH. The trade is explicit: 1.8 times the hashrate for 2.2 times the power. Stock is the efficiency play; the overclock is the odds play, because in solo mining your chance of finding a block scales directly with hashrate.
All figures carry a ±15% variance. Two physically identical ASICs never perform identically: microscopic differences in the manufacturing process mean one chip holds 600 MHz at lower voltage while its twin needs more voltage for the same clock. Miners call this the silicon lottery, and it is why published numbers are ranges, not promises, on every miner.
The ceiling is cooling, not silicon. In internal testing with an AIO hydro cooler mounted to the BM1373 pair, Solo Satoshi pushed a Naja Duo to 11,623 GH/s at 158.8 W (13.7 J/TH) with the ASICs holding 46 °C at 1.21 V core. That is 11.6 TH/s from a two-chip board. Liquid moves heat off the dies faster than any air cooler of this size can, and colder silicon runs stable at frequencies that would crash an air-cooled board. Because the full design is open source, that same modding headroom belongs to the community: swap the cooler, and the board will follow.
The Naja Duo Against the Full Bitaxe Lineup
The Naja Duo enters as the most efficient Bitaxe ever released and the second fastest at stock settings, behind only the six-chip, hydro-cooled Gamma Hex. All figures are default settings from live Solo Satoshi product data.
| Model | ASIC Chips | Default Hashrate | Power Draw | Efficiency |
|---|---|---|---|---|
| Bitaxe Gamma 602 | 1× BM1370 | 1.2 TH/s | ~18 W | ~15 J/TH |
| Bitaxe Gamma Duo 650 | 2× BM1370 | 1.63 TH/s | ~25.8 W | ~15 J/TH |
| Bitaxe GT 801 | 2× BM1370 | 2.15 TH/s | ~43 W | ~18 J/TH |
| Bitaxe Naja Duo 1201 | 2× BM1373 | 4.4 TH/s | ~42 W | ~9.5 J/TH |
| Bitaxe Gamma Hex 1300 | 6× BM1370 | 8.4 TH/s | ~140 W | ~16 J/TH |
The pattern is unambiguous. Every BM1370 board operates between 15 and 18 J/TH; the BM1373 drops the Naja Duo to 9.5 J/TH. Per watt, the Naja Duo produces 74% more hashrate than the Gamma Hex and roughly double the GT 801. Scale it and the gap widens: two Naja Duos deliver 8.8 TH/s at 84 W, out-hashing the 140 W Gamma Hex with 40% less power, on two quiet 92mm fans instead of a radiator. View the full Bitaxe lineup here.
Why the Naja Duo Ships at Default Clocks
Several BM1373 miners announced by other manufacturers in 2026 ship factory-overclocked, advertising 10 TH/s. The bigger number wins the spec-sheet comparison, but the owner pays for it every hour the machine runs: 20 to 30% more energy per terahash, more heat and noise, and constant stress on the voltage regulator and power supply, which can shorten component lifespan.
Push the overclock to its maximum and the math collapses entirely. At the far end of the curve, a BM1373 miner runs right back up near 15 J/TH, which is BM1370 territory. At that point you have paid a next-generation premium for last-generation efficiency, and a cheaper BM1370 board delivers the same joules per terahash without the hype tax. The BM1373’s defining advantage is single-digit efficiency.
The Naja Duo ships at 327 MHz, its most efficient operating point, and hands the headroom to the end user. AxeOS exposes custom frequency and core voltage controls as ordinary dashboard settings, giving the owner the freedom to tune the device as they wish. Due to the silicon lottery, this is also the technically correct default: a factory-wide overclock must be tuned for the weakest chips a manufacturer expects to ship, leaving strong chips underused and weak chips at the edge of stability. Shipping at stock lets each owner step frequency up one tier at a time, with live per-chip temperature data on screen, and find their specific unit’s true ceiling, following the Bitaxe overclocking guide. The 11.6 TH/s hydro result shows how far that ceiling moves when cooling improves. That headroom belongs to the user, not the marketing page.
Operating Costs and Heat Output
At default settings the Naja Duo consumes about 30.1 kWh per month running 24/7, roughly what a modern refrigerator uses in a week. That is $3.61 per month at $0.12 per kWh, $4.51 at $0.15, and $6.02 at $0.20. A full year of default operation at the US-average $0.15 rate costs about $54 in electricity for 4.4 TH/s of continuous hashrate.
Overclocked, monthly consumption rises to about 66.2 kWh: $7.95 at $0.12 per kWh and $9.94 at $0.15. Heat output stays modest either way, roughly 143 BTU/hr at stock and 314 BTU/hr overclocked. For scale, a sleeping adult emits about 300 BTU/hr, so even the overclocked Naja Duo warms a desk, not a room. The fan’s 22.4 dBA maximum sits below that of a quiet library, making the unit bedroom and office friendly. Exact profitability at any electricity rate and the current network difficulty can be modeled with the Bitcoin mining profitability calculator.
Board Design: Power Delivery, Telemetry, and Display
The 1201 board is engineered around the overclock profile rather than the stock numbers. Power arrives over a 12V XT30 connector, a compact locking plug that handles far more current than a barrel jack, now positioned on the back of the board so the power cable routes behind the unit for cleaner cable management. It feeds a 2-phase Texas Instruments TPS546024A voltage regulator. Two phases halve the load on each, spread heat across the board, and smooth voltage ripple, which is what keeps a 1,120 mV overclock stable for months instead of minutes.
The back of the board also carries three 12V fan headers, put there deliberately for community modding. Push-pull air setups, radiator fans for an AIO conversion, or a full custom cooling loop can all run straight off the board with no splitters or external controllers, and the 11.6 TH/s hydro result is exactly the kind of build those headers invite.
Telemetry is the other half of the story. Each BM1373 reports its own temperature to AxeOS, a first for the Bitaxe line. On single-sensor boards, one chip can run 10 degrees hotter than the reading suggests; here, throttling and fan curves follow the hotter chip, so protection kicks in when it is actually needed.
The display is a generational fix, not just an upgrade. Older Bitaxes used a small 0.91″ OLED in a friction-fit socket, the line’s most common failure point: modules worked loose, disconnected, and burned out over time. The Naja Duo replaces it with a 1.9″ 170 × 320 color LCD connected via ribbon cable.
The dashboard and LCD surface the same live data: hashrate, per-chip temperature, voltage, power draw, fan RPM, and best difficulty. The Naja Duo runs the standard open Bitaxe API, so that telemetry is compatible with your favorite hashrate monitoring tools, like the HashWatcher app, out of the box.
The rest of the board follows the same serviceability logic. The onboard ESP32-S3 microcontroller runs open-source esp-miner firmware over 2.4 GHz Wi-Fi, with dedicated Boot and Reset buttons, so recovering or restarting the miner never means pulling the power cable. A USB-C port handles flashing and full recovery from a browser, no soldering or special tools. Cooling is off-the-shelf by design: a Thermalright AXP90-X47 low-profile heatsink and a standard 92mm slim PWM fan that costs $13 to replace, not a proprietary module. The optional 124W power supply runs the full overclock at 74% load, comfortably inside the 80% load threshold recommended for continuous 24/7 duty.
Setup, Firmware, and Monitoring
Setup takes about 5 minutes. Power the unit and it broadcasts its own Wi-Fi hotspot; join it from a phone, computer, or tablet, enter your home network credentials, then open the IP address shown on the LCD in any browser. From there, AxeOS needs exactly two decisions: the on-chain Bitcoin address that receives a block reward (a bc1q SegWit address keeps fees lowest), and a pool. Solo miners point at Public Pool or Solo CKPool, which coordinate work but pay the full reward to whoever finds the block; miners who prefer small steady payouts can point the same hardware at a payout pool instead. Change your mind later and it is a one-field edit.
Firmware updates are available through the AxeOS interface or over USB-C through the Bitaxe web flasher. The firmware itself is mainline esp-miner, maintained by the Open Source Miners United (OSMU) community, so the Naja Duo receives the same ongoing updates, fixes, and features as the rest of the Bitaxe family rather than a forked, vendor-locked build. The step-by-step walkthrough with screenshots is in the Bitaxe setup guide.
Availability
The Bitaxe Naja Duo starts at $389.99 and is available exclusively at Solo Satoshi: 100% assembled in the USA, tested, firmware flashed, and shipped same day from Conroe, Texas on orders placed before 12 PM CT. Every unit includes the 1.9″ color LCD, a black 3D printed stand, and a 90-day warranty. The optional 124W XT30 power supply is available with US, UK, EU, or AU cords.
Solo Satoshi is a legit and trusted seller on the official bitaxe.org vendor list, working directly with the open-source developers behind the project. That standing is backed by 500+ verified reviews and 50,000+ devices shipped to 70+ countries since May 2024.
