Meta launches Muse Spark Open, optimized for Mac Studio with M5 Ultra

Meta unveiled Muse Spark Open, an open-weight multimodal model optimized to run on Mac Studio with Apple’s M5 Ultra.

The model has 816 billion total parameters, with 42 billion active, and a one-million-token context window. Meta positions it for coding, long-horizon agentic tasks, complex software engineering and multi-step reasoning.

Two Mac Studios share the model

Meta used the latest version of MLX, Apple’s open-source framework designed for the unified memory architecture of Apple silicon.

Each Mac Studio with M5 Ultra can provide up to 512GB of memory to its integrated GPU. Meta says two machines can hold the full model, while the chip’s 1.2TB/s memory bandwidth can read the data needed for each token.

On-device workflow tests

Meta said it tested agentic workflows locally through Muse Code. The tests included making bug fixes and adding features to Ice Cubes, an open-source Mastodon client, completing a full build, and operating DaVinci Resolve while reviewing footage frame by frame and cropping selected moments vertically.

Muse Spark Open is available now through Hugging Face. Apple separately described MLX as a way for researchers and developers to experiment locally with new models and methods in a private environment.

Apple and Meta resume cooperation

The companies have been working together for several months, Meta AI chief Alexandr Wang told Axios. He also credited former Apple executive Daniel Gross with playing a major role in helping the companies cooperate.