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Qwen3.8-Flash-Next on a 48GB M5 Pro MBP: ~20 tok/s in chat, but slow prefill makes agent use unpractical

This story is from 2026-09-12. It is preserved in the archive; the latest stories are on the live feed.

I’ve been testing Unsloth’s UD-IQ1_M GGUF on my M5 Pro MacBook Pro with 48GB unified memory, using llama.cpp b10930 (commit 56381e407). Mmap initially caused Metal OOM, even with all experts on CPU. Switching to --load-mode none --lazy-mode on resolved those errors in my tests while keeping the PLE…

Read the full story at r/LocalLLM ↗

Timeline · 3 reports

  1. 2026-09-14 04:30 · r/LocalLLaMA
    Data point: Qwen3.8-Flash-Next PP/TG speed on M3 Ultra
  2. 2026-09-12 21:08 · r/LocalLLaMA
    Qwen3.8 Flash Next now at 1.2k t/s prefill on Strix Halo
  3. 2026-09-12 15:27 · r/LocalLLM
    Qwen3.8-Flash-Next on a 48GB M5 Pro MBP: ~20 tok/s in chat, but slow prefill makes agent use unpractical

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