# Meta releases Muse Spark Open, an 816B open-weight model it runs on two Mac Studios

> OnPrem World · https://onpremworld.com/en/news/2026-10-meta-muse-spark-open · CC BY 4.0

Published: 2026-10-15 · Models

Meta released Muse Spark Open on October 15, an open-weight, natively multimodal model with 816B total parameters, 42B of them active, and a 1M-token context window, aimed at coding and agentic work. The weights are on Hugging Face, where access must be requested, together with an NVFP4 version, under the Muse Model License, which has limited commercial terms. Meta says the model runs on SGLang, vLLM, TensorRT-LLM, Transformers, Apple MLX, llama.cpp and Unsloth, and it demonstrated it on two Mac Studios with M5 Ultra, each with up to 512 GB of unified memory. It is also offered through hosted APIs such as Groq, Fireworks AI, Together AI and OpenRouter.

## Why it matters locally

A frontier-size open model from a major US lab now has an official path to run on desk-side hardware, not only in a data center.

## For the market

Meta calls it the most capable US open-weight model to date, and making it available on Hugging Face, three big clouds and seven API providers at once shows it wants wide adoption despite the limited licence. Showcasing Apple hardware rather than only GPUs likely strengthens the Mac Studio's case as a quiet alternative to a GPU server for very large models.

## In plain words

Meta has handed out one of its biggest AI models so anyone with the right machines can run it at home or in the office. It is still huge: Meta's own demo needed two top-spec Mac Studios working together.

## For practitioners

Only 42B parameters are active per token, so speed depends more on memory bandwidth than on total size, but the full 816B must still fit in memory; plan for two 512 GB M5 Ultra Mac Studios with MLX, or a multi-GPU server with the NVFP4 weights. Apple says the 512 GB Mac Studio configuration ships in late October 2026. Read the Muse Model License before any commercial deployment, and request Hugging Face access early because the repos are gated.

## Source

[Introducing Muse Spark Open (Meta AI)](https://research.meta.ai/blog/muse-spark-open)

## On this site

- Hardware: [M5 Ultra](https://onpremworld.com/en/hardware/apple-m5-ultra.md)

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Summaries are written by OnPrem World from the official source. We link to the original and never republish it.