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Main Authors: Kim, Youngeun, Lee, Seunghwan, Jung, Aecheon, Ryu, Bogon, Hong, Sungeun
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2503.06921
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author Kim, Youngeun
Lee, Seunghwan
Jung, Aecheon
Ryu, Bogon
Hong, Sungeun
author_facet Kim, Youngeun
Lee, Seunghwan
Jung, Aecheon
Ryu, Bogon
Hong, Sungeun
contents Model merging enables efficient multi-task models by combining task-specific fine-tuned checkpoints. However, storing multiple task-specific checkpoints requires significant memory, limiting scalability and restricting model merging to larger models and diverse tasks. In this paper, we propose quantizing task vectors (i.e., the difference between pre-trained and fine-tuned checkpoints) instead of quantizing fine-tuned checkpoints. We observe that task vectors exhibit a narrow weight range, enabling low precision quantization (e.g., 4 bit) within existing task vector merging frameworks. To further mitigate quantization errors within ultra-low bit precision (e.g., 2 bit), we introduce Residual Task Vector Quantization, which decomposes the task vector into a base vector and offset component. We allocate bits based on quantization sensitivity, ensuring precision while minimizing error within a memory budget. Experiments on image classification and dense prediction show our method maintains or improves model merging performance while using only 8% of the memory required for full-precision checkpoints.
format Preprint
id arxiv_https___arxiv_org_abs_2503_06921
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Task Vector Quantization for Memory-Efficient Model Merging
Kim, Youngeun
Lee, Seunghwan
Jung, Aecheon
Ryu, Bogon
Hong, Sungeun
Machine Learning
Model merging enables efficient multi-task models by combining task-specific fine-tuned checkpoints. However, storing multiple task-specific checkpoints requires significant memory, limiting scalability and restricting model merging to larger models and diverse tasks. In this paper, we propose quantizing task vectors (i.e., the difference between pre-trained and fine-tuned checkpoints) instead of quantizing fine-tuned checkpoints. We observe that task vectors exhibit a narrow weight range, enabling low precision quantization (e.g., 4 bit) within existing task vector merging frameworks. To further mitigate quantization errors within ultra-low bit precision (e.g., 2 bit), we introduce Residual Task Vector Quantization, which decomposes the task vector into a base vector and offset component. We allocate bits based on quantization sensitivity, ensuring precision while minimizing error within a memory budget. Experiments on image classification and dense prediction show our method maintains or improves model merging performance while using only 8% of the memory required for full-precision checkpoints.
title Task Vector Quantization for Memory-Efficient Model Merging
topic Machine Learning
url https://arxiv.org/abs/2503.06921