MXBM — an open-source BeamHash III GPU miner

Beam has had GPU miners for years, but none of the fast ones are open source.

MXBM is an open one. A BeamHash III miner written from scratch against Beam's published spec, Apache-2.0, all source on GitHub.

https://github.com/Maxnflaxl/MXBM

Speed

On a 4070 Ti SUPER at stock, CUDA does 74.4 sol/s and OpenCL does 63 sol/s. lolMiner does about 54 sol/s on the same card and won't go higher at any setting.

It depends on your power cap though:

From about 120 W up MXBM is faster and more efficient. Below that lolMiner is still ahead by a few percent, so if you run your cards capped very low it may still be the better pick for now. That's what I'm working on next.

What you need

• An NVIDIA card from the GTX 16 / RTX 20 series or newer for the CUDA backend. Older NVIDIA and AMD cards run on OpenCL, which is slower.
• 3 GB of VRAM. With 8 GB or more you get the fastest memory layout.
• Linux or Windows. Apple Silicon works too via Metal, see below.

Dev fee

1%. One 36-second round per hour. That's what the closed miners charge, so going open costs you nothing extra.

It shows up on its own row in the stats and the API. Fee rounds are tracked separately from your own shares. --dev-fee raises it, nothing lowers it.

Other things it does

• Multi-GPU, including mixed rigs where some cards run CUDA and others OpenCL.
• Overclocking from the command line: --pl, --cclk, --mclk, offsets, fan.
• --tune measures your card's power curve and tells you where to cap it.
• --apiport serves a small browser dashboard and a /summary JSON endpoint.
• A watchdog that exits with a restartable code if a card stalls.
• lolMiner-style console and command line, so your scripts mostly just work.

For fun

There's a native Metal backend for Apple Silicon. It does 18.8 sol/s on an M3 Max, which nobody should mine with, but it was interesting to write. There's also a CPU solver (--solver ref, needs the Beam core repo at build time) that's far too slow to mine with; it's there to check the GPU results.

What would help

Numbers from cards I don't own. Run

mxbm --report

and it benchmarks your card, measures its power curve and prints a markdown block you can paste into an issue. Nothing is uploaded. So far I have a 4070 Ti SUPER, 4070 SUPER, 3060 Ti, GTX 1660 Ti and an M3 Max. Turing looks slower than it should and I'm looking into it.

There's no AMD (HIP) backend yet, so AMD cards run on OpenCL. Contributions welcome.

Try it out and let me know what you think!

Discussion: https://forum.0xmx.net/d/204-mxbm-an-open-source-beamhash-iii-gpu-miner/

Telegram: https://t.me/mxbm_miner