Bitaxe Gamma (600) & the BM1370 — What you need to know
Welcome to the Bitaxe hardware corner of OSMU! 
This thread is a starting point for anyone running, building, or just curious about the Bitaxe Gamma (600) — the open-source solo miner built around Bitmain’s BM1370 ASIC. Drop your questions, mods, and benchmarks below.
What’s the BM1370?
The BM1370 is the SHA256 mining ASIC most commonly found in the Antminer S21 Pro, and it’s the chip powering the Bitaxe Gamma. Like its predecessors (BM1366, BM1368), it’s officially undocumented by Bitmain — most of what we know has been reverse-engineered by this community.
A few key specs:
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Nominal hashrate: ~1 to 1.4 TH/s per chip
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Efficiency: ~15 J/TH (the best of any chip currently used in a Bitaxe)
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Serial protocol: UART
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Voltage domains: Three internal VDD rails (VDD1, VDD2, VDD3) plus 0.8V and 1.2V IO rails
For the full pinout and details, see the OSMU Lab page: osmu.wiki/osmu-lab/bm1370
Why the Gamma is a big deal
The Gamma is currently the most efficient single-chip Bitaxe you can build. Compared to earlier generations:
| Bitaxe | Chip | Efficiency |
|---|---|---|
| Max (100) | BM1397 | ~30+ J/TH |
| Ultra (200) | BM1366 | ~21 J/TH |
| Supra (400) | BM1368 | ~17 J/TH |
| Gamma (600) | BM1370 | ~15 J/TH |
That means more hashes per watt — better for solo lottery mining, lower heat, quieter fans, and a lower power bill running 24/7.
Things worth discussing here
A few starter prompts — feel free to reply to any of these or start your own thread:
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Tuning: What voltage/frequency combo are you running on your Gamma? What’s your sweet spot for stability vs. hashrate? -
Cooling: Stock heatsink + fan, or have you modded it? Any temp readings from the on-chip diode (TEMP_P / TEMP_N pins)? -
PSU choice: What are you powering yours with? -
Solo luck: Has anyone hit a block (or come close) on a Gamma yet? Share the story! -
Builds & mods: Custom cases, BitHalo setups, cluster builds — post pics.
Useful links
Happy hashing — and welcome aboard. 