Dev runs 125B Qwen model locally on M3 Max at 70 tok/s via MLX

mayfer · x · 2026-08-28

A developer verified the native performance of Qwen 3.8 Flash Next (125B-A6B) on Apple Silicon using mlx-serve. On an M3 Max (128GB), the setup achieved 70 tok/s serial decoding and 300 tok/s prefill, successfully handling 32k token tasks with 20GB memory remaining.

The implementation uses Zig + Metal without Python. Key optimizations include hyper-connection residual streams, n-gram embeddings gathered directly from disk, sparse attention past 2k tokens, and 5 new Metal kernels. The model also supports image and video input.

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