Bitmain Antminer B7 (96Kh)

The Bitmain Antminer B7 is a legacy, air-cooled ASIC built for the Tensority proof-of-work algorithm that once secured the Bytom (BTM) blockchain. It hashes at roughly 96 KH/s while pulling about 528 W at the wall. Released in Bitmain’s 2018-2019 altcoin-ASIC wave, it is now valued for collecting, learning and supplemental heat rather than profit.

Antminer B7 at a glance

Tensority and the Bytom blockchain

Unlike almost every other Antminer, the B7 was never a Bitcoin miner. It targets Tensority, the proof-of-work algorithm behind Bytom (BTM). Tensority is unusual: it was designed around large matrix and tensor multiplications, the same math that powers neural-network inference. Bytom’s stated goal was an algorithm that AI-acceleration silicon could also mine, blurring the line between a hashing ASIC and a tensor-math accelerator. That ambition is the reason a dedicated chip like the one inside the B7 exists at all.

Because the B7 hashes Tensority rather than SHA-256, two things follow that shape the rest of this page. First, its performance is quoted in kilohashes per second (KH/s), not terahashes, so it is not directly comparable to an S9, S19 or S21. Second, an efficiency figure expressed in joules per terahash is meaningless here. The correct way to read the B7’s efficiency is roughly 5.5 joules per kilohash (528 W divided by 96 KH/s). If you have seen this model listed with a “5,500,000,000 J/TH” rating, that is an artifact of forcing a Tensority device through a Bitcoin-oriented calculator, not a real spec.

Chip and hashboard architecture

The B7 carries Bitmain’s purpose-built Tensority hashing ASIC, replicated across the unit’s hashboards and fed by a single control board inside the familiar Antminer chassis. Bitmain did not publish the Tensority chip’s internals to the same depth as its Bitcoin line (the BM1387, BM1397 and BM1398 generations), so D-Central treats the exact die SKU and per-board chip count as undocumented rather than guessing at a number.

What we can state with confidence comes from the control-board platform the B7 shares with the rest of Bitmain’s 2018-2019 catalog, hardware we have probed and repaired in-house since 2016. That generation is built around a Xilinx Zynq SoC pairing dual Arm Cortex-A9 cores (clocked around 667 MHz) with an FPGA fabric; the FPGA drives the hashing chains while the Arm side runs a Linux stack and the web dashboard. A single I2C bus links the controller to the on-board voltage regulation and temperature sensors, and the hashboards plug into the controller through Bitmain’s standard 18-pin connector.

One architectural detail matters more than any marketing number when you own or diagnose one of these units: voltage is regulated per domain, not per chip. The ASICs sit in series-connected strings, and a DC-DC stage holds a target voltage across a domain (a group of chips on a shared rail). There is no individual-chip voltage knob. That is why a single weak or shorted die can drag down an entire domain and present as a dead section of the board rather than a single bad chip.

Real-world power and efficiency

The 528 W nameplate is a wall figure for a stock unit in a reasonable ambient. As with every air-cooled ASIC, expect the number to drift with intake temperature, PSU age and fan condition: a tired power supply or clogged heatsinks raise draw for the same work. There is no meaningful undervolting or autotuning ecosystem for the B7 the way there is for modern SHA-256 hardware, so treat 528 W as roughly fixed rather than a starting point you can tune down.

For context on how tuning headroom, voltage domains and joules-per-unit-of-work behave on the hardware we do tune, see our ASIC power profiles database. It documents the per-domain frequency and voltage steps that modern Antminers expose, the runtime-calculated autotuner behavior of current firmware, and why a published efficiency number is only ever the starting point of a real-world curve. The B7 predates all of that: it runs at one operating point and stays there.

Firmware compatibility

The B7 ships with Bitmain’s stock firmware, a cgminer-derived stack with the classic Antminer web interface for pool configuration, status and basic diagnostics. That is essentially the whole story for this model.

The rich aftermarket firmware world that mining hackers rely on, BraiinsOS+, VNish, LuxOS and D-Central’s own DCENT_OS, is built exclusively for SHA-256 Antminers (the S9, S17, S19 and S21 families). None of it targets the Tensority hash engine, so there is no custom-firmware path to extra efficiency or features on a B7. Conveniences that live in that ecosystem, such as native Stratum V2 support (currently only in BraiinsOS+), simply do not exist in the Tensority world. DCENT_OS is our firmware for modern SHA-256 Antminers and does not apply to this device. If you are running a B7, plan around stock firmware and judge it on stock terms.

Common faults and troubleshooting

A B7 fails in the same ways any air-cooled Antminer of its era does. The usual suspects are a hashboard or chain dropping offline, temperature-sensor read errors, fan faults flagged by the controller, and outright PSU failure. Because Tensority is a niche, low-value chain today, the most common reason a B7 stops earning is simply that nobody is left to maintain it, not a single dramatic fault.

When you do need to diagnose one, work from symptoms rather than guesses. Our ASIC fault finder walks the standard decision tree, dead board versus dead PSU versus controller, fan errors, thermal trips, and how a per-domain voltage layout makes one bad die look like a missing section of the board. The logic transfers cleanly from our SHA-256 repair work to a B7, even though the chip is different. Start with the easy wins: confirm clean power, reseat the hashboard connectors, clear dust from the heatsinks and fans, and check that both fans actually spin before you ever suspect the silicon.

Repair and longevity

D-Central has repaired Antminers since 2016, and we are honest about what is and is not worth fixing. On a B7, the serviceable parts are the parts the whole Antminer line shares: the power supply, the fans and the control board all use common, repairable components, and a unit that is “dead” because of a failed PSU or a tired fan is usually an easy save.

The hard limit is the hashboard. Tensority ASICs are out of production and there is no donor-board supply to harvest, so a B7 board with dead chips is generally beyond economical repair, the replacement silicon simply does not exist. We respect what Bitmain built here, an early bet on AI-friendly proof-of-work, but we will always tell you plainly when a board is not worth the bench time rather than sell you a repair that cannot hold. For anything still serviceable, see our ASIC repair service.

Who the Antminer B7 is for today

This is not an income machine. Bytom’s value and network activity faded years ago, and Tensority mining no longer pays for its own electricity in any normal setting. Buy or keep a B7 for one of three honest reasons:

• Collecting and blockchain history — the B7 is a clean example of Bitmain’s brief push into AI-adjacent altcoin ASICs.
• Teardown and learning — it is a low-stakes platform for studying Antminer control boards, hashboard wiring and PSU behavior.
• Supplemental heat — at ~528 W it emits about 1,802 BTU/h, enough to take the edge off a small room, the same money you would spend on a space heater.

If your real goal is to learn mining hands-on at low power and low risk, a Bitaxe is a far better modern starting point: open-source, single-chip, a few watts, and an active community. If you want hashrate that actually earns, look at current SHA-256 hardware in our shop or browse the full ASIC miner database to compare efficiency tiers before you buy.

Generational context

The B7 belongs to Bitmain’s 2018-2019 expansion beyond Bitcoin, the same wave that produced dedicated miners for Ethash, Equihash, Blake and other altcoin algorithms. Within the Bytom line specifically, the earlier B3 introduced Tensority mining and the B7 arrived as the dramatically faster successor, a large multiple of the B3’s throughput in a similar single-box form factor.

That wave did not last. The crypto winter that followed, combined with declining interest in Bytom itself, hollowed out the market for single-algorithm altcoin ASICs almost as quickly as it appeared. Bitmain redirected its engineering back toward the SHA-256 line that became the S17, S19 and S21 generations, the hardware that defines mining today and the hardware D-Central tunes, repairs and builds firmware for. Viewed from 2026, the Antminer B7 is best understood as a well-built artifact of an ambitious detour, interesting for what it tried to do, but no longer a tool for making money.