Overview
Muse Spark Open is the most capable US open-weight model to date, the company says.
In case there was still any doubt about Meta's commitment to open models, the company is open-sourcing Muse Spark with a new open-weight model called Muse Spark Open. The 800-billion parameter model was optimized for Apple Silicon, but you'll need a staggering 1TB of RAM to run it locally.
Performance and Benchmarks
Meta calls Muse Spark Open the most capable US open-weight model to date. Benchmarks released by the company suggest Meta's model outperforms two leading Chinese models, GLM 5.3 and Kimi K3, on agentic tasks and visual reasoning.
Apple Silicon Integration
It's also the first model optimized to run locally on Apple's M5 Ultra-equipped Mac Studio machines. Apple's unified memory architecture lets the M5 Ultra's integrated GPU use up to 512 GB per Mac Studio, so two machines can hold an entire model, Meta explains. The result is two Mac Studios behave like one supercomputer with a terabyte of unified memory.
Muse Spark Open weights releasing today run great on new Mac Studios.
Hardware Investment
While Apple has announced the 512GB Mac Studio will be available in late October, any setup that can run Muse Spark Open will require a hefty investment. Muse Spark Open can also run on four 256GB M5 Ultra Mac Studios, which will cost roughly $38,000. That amount of compute is pretty squarely out of reach for typical individual developers. However, larger organizations that have been burning through token budgets might find investing in a few Mac Studios to be a viable option.
Muse Spark Open is available to download now from Hugging Face.
