Benchmarking Post-Training Quantization of Large Language Models under Microscaling Floating Point Formats

Fuente: arXiv
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Auteurs principaux: Zhang, Manyi, Li, Ji-Fu, Sun, Zhongao, Bai, Haoli, Zhen, Hui-Ling, Dong, Zhenhua, Yu, Xianzhi
Format: Preprint
Publié: 2026
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author Zhang, Manyi
Li, Ji-Fu
Sun, Zhongao
Bai, Haoli
Zhen, Hui-Ling
Dong, Zhenhua
Yu, Xianzhi
author_facet Zhang, Manyi
Li, Ji-Fu
Sun, Zhongao
Bai, Haoli
Zhen, Hui-Ling
Dong, Zhenhua
Yu, Xianzhi
contents Microscaling Floating-Point (MXFP) has emerged as a promising low-precision format for large language models (LLMs). Despite various post-training quantization (PTQ) algorithms being proposed, they mostly focus on integer quantization, while their applicability and behavior under MXFP formats remain largely unexplored. To address this gap, this work conducts a systematic investigation of PTQ under MXFP formats, encompassing over 7 PTQ algorithms, 15 evaluation benchmarks, and 3 LLM families. The key findings include: 1) MXFP8 consistently achieves near-lossless performance, while MXFP4 introduces substantial accuracy degradation and remains challenging; 2) PTQ effectiveness under MXFP depends strongly on format compatibility, with some algorithmic paradigms being consistently more effective than others; 3) PTQ performance exhibits highly consistent trends across model families and modalities, in particular, quantization sensitivity is dominated by the language model rather than the vision encoder in multimodal LLMs; 4) The scaling factor of quantization is a critical error source in MXFP4, and a simple pre-scale optimization strategy can significantly mitigate its impact. Together, these results provide practical guidance on adapting existing PTQ methods to MXFP quantization.
format Preprint
id arxiv_https___arxiv_org_abs_2601_09555
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Benchmarking Post-Training Quantization of Large Language Models under Microscaling Floating Point Formats
Zhang, Manyi
Li, Ji-Fu
Sun, Zhongao
Bai, Haoli
Zhen, Hui-Ling
Dong, Zhenhua
Yu, Xianzhi
Computation and Language
Artificial Intelligence
Microscaling Floating-Point (MXFP) has emerged as a promising low-precision format for large language models (LLMs). Despite various post-training quantization (PTQ) algorithms being proposed, they mostly focus on integer quantization, while their applicability and behavior under MXFP formats remain largely unexplored. To address this gap, this work conducts a systematic investigation of PTQ under MXFP formats, encompassing over 7 PTQ algorithms, 15 evaluation benchmarks, and 3 LLM families. The key findings include: 1) MXFP8 consistently achieves near-lossless performance, while MXFP4 introduces substantial accuracy degradation and remains challenging; 2) PTQ effectiveness under MXFP depends strongly on format compatibility, with some algorithmic paradigms being consistently more effective than others; 3) PTQ performance exhibits highly consistent trends across model families and modalities, in particular, quantization sensitivity is dominated by the language model rather than the vision encoder in multimodal LLMs; 4) The scaling factor of quantization is a critical error source in MXFP4, and a simple pre-scale optimization strategy can significantly mitigate its impact. Together, these results provide practical guidance on adapting existing PTQ methods to MXFP quantization.
title Benchmarking Post-Training Quantization of Large Language Models under Microscaling Floating Point Formats
topic Computation and Language
Artificial Intelligence
url https://arxiv.org/abs/2601.09555