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

User reports Qwen3.8 Flash-Next at 58 tok/s generation and 2,000 tok/s prefill on a Mac Studio M5 Ultra 256GB. Setup is MTPLX 2.12.0 with speculative decoding, 55 to 65 percent draft acceptance, 99 GB resident, 4k context. Four models run in slots on the same box; Gemma 4 26B 4-bit reaches 113 tok/s, Qwen 3.6 35B-A3B 114 tok/s, DeepSeek V4 Flash 4-bit 31 tok/s. DeepSeek prefill is from a single uncached 13,139-token request in 21.8 s. Clef-Flash 9B decision slot has a 259 ms median.