Layer-Wise High-Impact Parameter Ratio Optimization in Post-Training Quantization for Large Language Models

Fuente: arXiv
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Hauptverfasser: Pham, Cuong, Dung, Hoang Anh, Nguyen, Cuong C., Le, Trung, Carneiro, Gustavo, Do, Thanh-Toan
Format: Preprint
Veröffentlicht: 2025
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author Pham, Cuong
Dung, Hoang Anh
Nguyen, Cuong C.
Le, Trung
Carneiro, Gustavo
Do, Thanh-Toan
author_facet Pham, Cuong
Dung, Hoang Anh
Nguyen, Cuong C.
Le, Trung
Carneiro, Gustavo
Do, Thanh-Toan
contents Large language models (LLMs) have significantly advanced natural language processing, but their massive parameter counts create substantial computational and memory challenges during deployment. Post-training quantization (PTQ) has emerged as a promising approach to mitigate these challenges with minimal overhead. While existing PTQ methods can effectively quantize LLMs, they experience substantial accuracy loss at extremely low bit-widths, primarily due to high-impact parameters that significantly influence quantization performance. Several approaches address these issues by identifying and retaining the high-impact parameters in FP16 format. However, they apply fixed ratios of high-impact parameters across all layers, overlooking layer-wise sensitivity variations. In this paper, we propose a quadratic optimization framework that determines layer-specific ratios of high-impact parameters while considering inter-layer dependencies. We quantize high-impact parameters to moderate bit-widths, which often result in negligible performance degradation in quantized LLMs, while the remaining parameters can be quantized to extremely low bit-widths. Under the same resource-constrained budget, this allows for preserving more high-impact parameters than methods that keep selecting a few in FP16 format. Additionally, the proposed framework allows us to leverage an advanced quantization method that often requires extensive learnable parameters solely for high-impact parameters, while applying a computationally efficient method to the rest. Our approach achieves an effective balance between computational efficiency and model accuracy while maintaining high performance compared to state-of-the-art methods.
format Preprint
id arxiv_https___arxiv_org_abs_2511_17801
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Layer-Wise High-Impact Parameter Ratio Optimization in Post-Training Quantization for Large Language Models
Pham, Cuong
Dung, Hoang Anh
Nguyen, Cuong C.
Le, Trung
Carneiro, Gustavo
Do, Thanh-Toan
Machine Learning
Large language models (LLMs) have significantly advanced natural language processing, but their massive parameter counts create substantial computational and memory challenges during deployment. Post-training quantization (PTQ) has emerged as a promising approach to mitigate these challenges with minimal overhead. While existing PTQ methods can effectively quantize LLMs, they experience substantial accuracy loss at extremely low bit-widths, primarily due to high-impact parameters that significantly influence quantization performance. Several approaches address these issues by identifying and retaining the high-impact parameters in FP16 format. However, they apply fixed ratios of high-impact parameters across all layers, overlooking layer-wise sensitivity variations. In this paper, we propose a quadratic optimization framework that determines layer-specific ratios of high-impact parameters while considering inter-layer dependencies. We quantize high-impact parameters to moderate bit-widths, which often result in negligible performance degradation in quantized LLMs, while the remaining parameters can be quantized to extremely low bit-widths. Under the same resource-constrained budget, this allows for preserving more high-impact parameters than methods that keep selecting a few in FP16 format. Additionally, the proposed framework allows us to leverage an advanced quantization method that often requires extensive learnable parameters solely for high-impact parameters, while applying a computationally efficient method to the rest. Our approach achieves an effective balance between computational efficiency and model accuracy while maintaining high performance compared to state-of-the-art methods.
title Layer-Wise High-Impact Parameter Ratio Optimization in Post-Training Quantization for Large Language Models
topic Machine Learning
url https://arxiv.org/abs/2511.17801