Revisiting the Effectiveness of LLM Pruning for Test-Time Scaling

Fuente: arXiv
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Main Authors: Monjur, Ocean, Nahin, Shahriar Kabir, Chhabra, Anshuman
Format: Preprint
Published: 2026
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author Monjur, Ocean
Nahin, Shahriar Kabir
Chhabra, Anshuman
author_facet Monjur, Ocean
Nahin, Shahriar Kabir
Chhabra, Anshuman
contents Large Language Models (LLMs) now exhibit remarkable reasoning capabilities through test-time compute scaling (TTS), with impressive performance across math and coding benchmarks. In parallel, research in model compression has developed pruning methods that seek to remove redundant/detrimental parameters without sacrificing task performance. The intersection of these two research advancements lays the foundation for our work. Specific to reasoning LLMs, prior work has shown that structured pruning (methods which remove entire set of layer blocks), significantly degrades TTS reasoning performance. However, in this work, we revisit this assumption and investigate whether unstructured pruning (methods that carefully remove only certain redundant/detrimental weights) exhibits similar limitations. Surprisingly, our extensive experiments across four reasoning benchmarks on two reasoning LLMs: s1.1-7B and Qwen3-8B, consistently show that unstructured pruning augments TTS performance compared to structured pruning, and at times can even outperform the unpruned full-weight LLMs. Furthermore, we also empirically study the impact of different layer-wise sparsity allocation strategies, which are an important parametric choice for instantiating these unstructured methods. These findings challenge the conventional notion that pruning always reduces TTS performance and in fact, suggest that carefully undertaken pruning can retain TTS effectiveness.
format Preprint
id arxiv_https___arxiv_org_abs_2604_25098
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Revisiting the Effectiveness of LLM Pruning for Test-Time Scaling
Monjur, Ocean
Nahin, Shahriar Kabir
Chhabra, Anshuman
Artificial Intelligence
Computation and Language
Machine Learning
Large Language Models (LLMs) now exhibit remarkable reasoning capabilities through test-time compute scaling (TTS), with impressive performance across math and coding benchmarks. In parallel, research in model compression has developed pruning methods that seek to remove redundant/detrimental parameters without sacrificing task performance. The intersection of these two research advancements lays the foundation for our work. Specific to reasoning LLMs, prior work has shown that structured pruning (methods which remove entire set of layer blocks), significantly degrades TTS reasoning performance. However, in this work, we revisit this assumption and investigate whether unstructured pruning (methods that carefully remove only certain redundant/detrimental weights) exhibits similar limitations. Surprisingly, our extensive experiments across four reasoning benchmarks on two reasoning LLMs: s1.1-7B and Qwen3-8B, consistently show that unstructured pruning augments TTS performance compared to structured pruning, and at times can even outperform the unpruned full-weight LLMs. Furthermore, we also empirically study the impact of different layer-wise sparsity allocation strategies, which are an important parametric choice for instantiating these unstructured methods. These findings challenge the conventional notion that pruning always reduces TTS performance and in fact, suggest that carefully undertaken pruning can retain TTS effectiveness.
title Revisiting the Effectiveness of LLM Pruning for Test-Time Scaling
topic Artificial Intelligence
Computation and Language
Machine Learning
url https://arxiv.org/abs/2604.25098