DeepSeek V4.1 Flash 552B (16B active)

User reports DeepSeek V4.1 Flash running at 1M-token context on a 96 GB Apple M5 Ultra, with decode of ~30–62 tok/s and prefill of ~915–1,800 tok/s. Setup is Sushi 1.5.1 on MLX 0.32.3 with a 1.75bpw STQ pack (~310 GB on disk), streaming routed experts from SSD with an 88 GB SSD budget; the 189 GB Engram tables are read from SSD and never loaded into GPU memory. First token takes 1.2–70 s from 1k to 128k context, and ~17 min cold at 1M where decode falls to ~23 tok/s. User calls it clearly smarter than the Qwen 3.8 Flash Next 2.75 quant they run daily, but too slow for daily chat or coding loops; the Qwen comparison is from a different day and protocol.