Qwen3.5 397B (17B active)

User reports Qwen3.5 397B-A17B at 33 t/s generation and 386.4 t/s prompt processing on a single Mac Studio with an M3 Ultra and 512 GB unified memory. Setup is mlx-vlm with 4bit MLX, run at long context with 34,448 actual input tokens and 128 generated tokens per run, three runs, peak memory 234.9 GB. The figures are medians; prompt processing p10/p90 are 359.4 and 428.1 t/s, and median wall time was 105 seconds. KV quantization, flash attention and speculative decoding are not exposed, and cold-cache prefill is not established.