Qwen3.8 125B (6B active) Flash-Next

User reports Qwen3.8-Flash-Next 125B at 43.0 tok/s decode and 656 tok/s prefill on a single Ryzen AI Max+ 395 (Strix Halo, 128 GB unified memory). Setup is a llama.cpp Vulkan fork with 57 patches, Unsloth UD-Q4_K_XL (111 GB), 8k context, MTP speculative decoding, single request, no CPU offload. At 32k context decode is 40.1 tok/s and prefill 585 tok/s. Inside a tool call decode is about 55 tok/s (was 25), first token after a short tool result 0.4 s (was 1.5 s), and the agent loop over 12 shell commands runs at 16.2 tokens per wall-clock second (was 11.1). KL divergence against full-precision reference logits is 0.116 with 92.2% same top-1 token. The user notes the runtime is reproducible bit for bit and that a PaoAI BALANCED-2.1 file ran 6-9% faster but with about 5x the KL divergence (0.589).