Perplexity Q5_K_S vs NVFP4 on Qwen 3.5 122B

#18
by qcsmire - opened

Now when NVFP4 finally start to work on the GPU, I did a perplexity comparison between Q5_K_S and NVFP4 using Qwen 3.5 120B A10.
I used unsloth/Qwen3.5-122B-A10B-GGUF model
and I converted txn545/Qwen3.5-122B-A10B-NVFP4 (created by NVIDIA Model Optimizer) to gguf (see discussion #20711 in llama.cpp on github, for how to)

Q5_K_S:
Final estimate: PPL = 4.6761 +/- 0.03024

NVFP4:
Final estimate: PPL = 4.7424 +/- 0.03087

Is this result what can be expected of NVFP4?
To me, they look approximatly comparable vs. the lower quality of MXFP4 ?

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