Developers can now run Meta's Muse Spark Open model directly on high-end Macs, the result of a collaboration announced on Thursday between two companies that have spent years trading blows. Mark Zuckerberg, Meta's chief executive, wrote on X that the model, with its weights going out the same day, "runs great on new Mac Studios thanks to work with @johnternus and Apple."
Muse Spark Open is an 816-billion-parameter open-weight model built on a mixture-of-experts design. Its weights are free to download, and the model is meant to run across clusters of two to four Mac Studio machines fitted with Apple's M5 Ultra chips and plenty of unified memory. Apple tuned the setup for coding, video analysis and other agentic jobs, using its MLX framework to spread inference across the machines.
Apple's chief executive John Ternus replied to Zuckerberg: "Congrats to the team!" He added that Mac Studio "keeps pushing the boundaries of on-device AI" and called it remarkable to run a model of that size so efficiently from a desk.
Meta's AI chief Alexandr Wang said the two sides had been at it for months, with Daniel Gross, a former Apple executive now at Meta, central to the work. Wang described it as bringing leading agent features to the desktop for the first time on the M5 Ultra Mac Studios. The model is not Meta's strongest, he said, but it should appeal to developers wanting to test ideas at a smaller scale before scaling up.
The alliance is unusual given the record. The two had not partnered publicly since around 2017, and the relationship soured over Apple's 2021 privacy changes that dented Meta's advertising revenue, as well as pointed remarks between Zuckerberg and former Apple boss Tim Cook. Asked whether this points to something broader, representatives of both firms declined to say.
Running a model on local hardware is pitched as better for security, cheaper over time, and less dependent on cloud data centres. A Mac Studio with the M5 Ultra and at least 256GB of memory starts at $10,799, and stringing several together drives the bill up. Meta bought hundreds of Macs earlier this year for its own AI work.
Apple's wider AI strategy already leans on deals with OpenAI and Google for Apple Intelligence and Siri features, while Meta keeps building both proprietary and open-weight models under Wang.
