Custom Quantization Boosts R9700 by 5.8%
alphatrad · reddit · 2026-07-18
The author tuned a custom quantization format Q80ROCMFPX for three Radeon AI PRO R9700 cards, aiming to outperform generic Q8 on gfx1201.
Results
- Model size is 2.94% smaller than upstream Q80
- HumanEval: 140/164, tying with the original
- Full model decoding: 5.77%–5.87% faster
- Equal workload test: Median 5.82% faster, winning 17/18 paired groups, p=0.000965
- End-to-end agent total runtime: Only 2.21% faster, missing the author's 3% threshold
Constraints
- Currently cannot run directly on upstream llama.cpp, Ollama, LM Studio, or vLLM
- Requires the author's specific ROCmFPX fork and source compilation
- This optimization is primarily effective for gfx1201 / R9700, offering limited benefits for NVIDIA or other AMD cards
The author provided a full experimental repository and noted it would be helpful if more people reproduced the results and compared them against stock Q8.
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