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

User reports Qwen3.8 Flash-Next prefill at 1821 tok/s at 16k context on a Strix Halo 128GB (EVO-X2, Ryzen AI Max+ 395). Setup is a fork of Gufo with UD-IQ4_XS quant, offloading some GEMMs to the NPU while the GPU handles the rest. Output verified identical to GPU-only build across 30 long greedy prompts. Prefill improved from ~1700 tok/s with GPU only. Pinning the GPU fabric clock at max was required to avoid hard hangs and also gave a speedup by itself.