Meta built a huge open-weight AI model for Macs, but you'll need 1TB of RAM to run it

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. Meta, which has said it believes the US should not allow Chinese labs to lead on open-source AI, 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. It's also the first model optimized to run locally on Apple's M5 Ultra-equipped Mac Studio machines.