XQuant: Achieving Ultra-Low Bit KV Cache Quantization with Cross-Layer Compression

Fuente: arXiv
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Autores principales: Yang, Haoqi, Yao, Yao, Li, Zuchao, Qi, Baoyuan, Liu, Guoming, Zhao, Hai
Formato: Preprint
Publicado: 2025
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author Yang, Haoqi
Yao, Yao
Li, Zuchao
Qi, Baoyuan
Liu, Guoming
Zhao, Hai
author_facet Yang, Haoqi
Yao, Yao
Li, Zuchao
Qi, Baoyuan
Liu, Guoming
Zhao, Hai
contents Large Language Models (LLMs) have demonstrated remarkable capabilities across diverse natural language processing tasks. However, their extensive memory requirements, particularly due to KV cache growth during long-text understanding and generation, present significant challenges for deployment in resource-constrained environments. Quantization has emerged as a promising solution to reduce memory consumption while preserving historical information. We propose XQuant, a training-free and plug-and-play framework that achieves ultra-low equivalent bit-width KV cache quantization. XQuant introduces two key innovations: a computationally negligible data-free calibration method and cross-layer KV cache compression, enabling quantization to sub-1.4 bits. Extensive experiments on TruthfulQA and LongBench demonstrate that XQuant outperforms state-of-the-art methods (e.g., KIVI-2bit and AsymKV-1.5bit) by achieving lower bit-width while maintaining superior performance, establishing a better trade-off between memory efficiency and model accuracy.
format Preprint
id arxiv_https___arxiv_org_abs_2510_11236
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle XQuant: Achieving Ultra-Low Bit KV Cache Quantization with Cross-Layer Compression
Yang, Haoqi
Yao, Yao
Li, Zuchao
Qi, Baoyuan
Liu, Guoming
Zhao, Hai
Computation and Language
Large Language Models (LLMs) have demonstrated remarkable capabilities across diverse natural language processing tasks. However, their extensive memory requirements, particularly due to KV cache growth during long-text understanding and generation, present significant challenges for deployment in resource-constrained environments. Quantization has emerged as a promising solution to reduce memory consumption while preserving historical information. We propose XQuant, a training-free and plug-and-play framework that achieves ultra-low equivalent bit-width KV cache quantization. XQuant introduces two key innovations: a computationally negligible data-free calibration method and cross-layer KV cache compression, enabling quantization to sub-1.4 bits. Extensive experiments on TruthfulQA and LongBench demonstrate that XQuant outperforms state-of-the-art methods (e.g., KIVI-2bit and AsymKV-1.5bit) by achieving lower bit-width while maintaining superior performance, establishing a better trade-off between memory efficiency and model accuracy.
title XQuant: Achieving Ultra-Low Bit KV Cache Quantization with Cross-Layer Compression
topic Computation and Language
url https://arxiv.org/abs/2510.11236