48% speedup: optimized llama.cpp settings for Qwen3.8-Flash-Next on Ryzen AI Max+ 395

Prudence-0 · reddit · 2026-11-09

A Reddit user shares llama.cpp launch parameters that deliver a 48% performance boost and more consistent tok/s for Qwen3.8-Flash-Next on a Ryzen AI Max+ 395 with 96GB unified memory, at contexts beyond 64k—without resorting to third-party inference engines.

Key settings include --fit on with --flash-attn, KV cache quantized to q80 with --kv-unified, a 131072 context with --ctx-checkpoints 128, dual parallel continuous batching, and ngram speculative decoding (match 24 / max 16 / min 4). Sampling: temp 1.0, top-p 0.95, top-k 20.

The author also recommends the Qwen3.8-Flash-Next-Uncensored-Gufo-Q4Mix quant as a solid quality/performance balance. The attached screenshot shows 67 requests processing 3.34M prompt tokens with 3.28M cached.

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