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

User reports DeepSeek-V4.1-Flash at 19.3 tok/s decode (C1) on a single RTX 3090 24GB with 503 GiB DDR4 and NVMe. Setup is vLLM 0.13 with EXL3 3.0 bpw quantization, fp8 KV cache, 262,144-token context, and CPU expert offload. All 15,360 routed experts are pinned in host RAM (190.5 GiB), with an AVX2 CPU tier computing cold decode misses and an elastic VRAM expert cache holding the hottest experts. Decode scales to 24.0 tok/s at 2 streams and 26.6 tok/s at 4 streams. Prefill ranges from 690 to 790 tok/s across 8k to 261k tokens. An experimental Intel Arc B70 expert tier reached 41.3 tok/s at 4 streams (+55%), but quality A/B is pending. Prefill fidelity failed the inherited guard (top-1 0.9856 vs 0.988 required, mean KL 0.0068 vs 0.00103 allowed).