Offloading only "hot" MoE experts to VRAM boosts llama.cpp throughput 50%

nbvehrfr · reddit · 2026-08-29

A developer forked llama.cpp with a twist: when a MoE model doesn't fit entirely in VRAM (here Qwen 3.8 Flash Next), instead of offloading whole layers, only the "hot" experts go to VRAM—raising throughput from 20 t/s to 30 t/s (+50%).

Key observation: certain groups of experts stay relatively stable across coding, refactoring and code-review workloads, making them worth pinning. PR: github.com/timadinorth/llama.cpp/pull/1.

Caveats: tested only on coding workloads, and only useful when the full model exceeds VRAM. The author doubts upstream will accept it—the low-level implementation was written by Opus, and he doesn't feel like defending every line.

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