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

User reports DeepSeek V4.1 Flash at 43.0 tok/s speculative decode on a single NVIDIA DGX Spark (GB10, 128 GB unified memory), using a custom YoungAi C/CUDA engine. Setup is a 113.6 GB VQ-8 base GGUF plus a ~40 MB per-domain sidecar; the 14.1k-token Agent request ran greedy with speculative decoding at 3.04 tok/round. Pure decode on the same request is 28.9-29.4 tok/s, and short-prompt greedy is 30.5-30.7 tok/s. Prefill is 1,055 tok/s on a 12.5k prompt, 940 tok/s on the 14.1k Agent request, and 671 tok/s on a 106.7k prompt (159 s TTFT). Domain sidecars raise top-1 agreement vs the original by +2.8 to +3.7 points across finance, code, law, medicine and science; the post-training file flips decisions on the solving request but does not generalize to held-out days.