Meta today announced the release of Muse Spark Open, which it says is the "most capable U.S. open-weight model to date."
Meta worked with Apple to bring Muse Spark Open to the Mac, and the model can run on a desktop setup with two 512GB Apple M5 Ultra Mac Studios running the latest MLX framework. Meta CEO Mark Zuckerberg thanked Apple CEO John Ternus for working with Meta.
@finkd Congrats to the team! Amazing to run a model of Muse Spark Open's caliber and scale this efficiently, right from your desk. Mac Studio keeps pushing the boundaries of on-device AI! — John Ternus (@johnternus) October 15, 2026
Muse Spark Open has 816 billion total parameters with 42 billion active parameters and a 1 million-token context window. It is meant for coding and agentic work, and Meta says it excels at extended tasks, multi-step reasoning, and software engineering.
The new Muse model was tuned to run on Mac Studio, and Meta says the Mac Studio paired with Muse Spark Open is the "best way to run a powerful model on your own desktop." From Meta:
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. And the chip's 1.2 TB/s of memory bandwidth is fast enough to read the small slice each token needs. The result is two Mac Studios behave like one supercomputer with a terabyte of unified memory.
Apple hasn't released the 512GB Mac Studio as of yet, but it's supposed to be coming later this month. It won't be cheap, because the 256GB Mac Studio is already priced over $10,000.
The model is available through API platforms at Baseten, Fireworks AI, Groq, Modal, Nebius, OpenRouter, and Together AI, with model weights downloadable from Amazon SageMaker AI, Google Cloud Model Garden, Hugging Face, and Microsoft Foundry Models. Muse Spark Open is free to download and has a license allowing limited commercial use.
Apple and Meta often argue more than they work together, so it is something of a surprise to see the two companies partnering for Muse Spark Open. "We're excited for mommy and daddy to be playing nice again," Meta's AI chief Alexandr Wang told Axios.
