From 2:4 to 8:16 sparsity patterns in LLMs for Outliers and Weights with Variance Correction

Egor Maximov, Yulia Kuzkina, Egor Shvetsov, Azamat Kanametov, Aleksandr Prutko, Maxim Zhelnin, Aleksei Goncharov


Abstract
As large language models (LLMs) grow in size, efficient compression techniques like quantization and sparsification are critical. While quantization maintains performance with reduced precision, structured sparsity methods, such as N:M sparsification, often fall short due to limited flexibility and sensitivity to outlier weights. We explore 8:16 semi-structured sparsity, demonstrating its ability to surpass the Performance Threshold—where a compressed model matches the accuracy of its uncompressed or smaller counterpart under equivalent memory constraints. Compared to 2:4 sparsity, 8:16 offers greater flexibility with minimal storage overhead (0.875 vs. 0.75 bits/element). We also apply sparse structured patterns for salient weights, showing that structured sparsity for outliers is competitive with unstructured approaches, leading to equivalent or better results. Finally, we demonstrate that simple techniques such as variance correction and SmoothQuant-like weight equalization improve sparse models performance.
Anthology ID:
2026.acl-industry.66
Volume:
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (ACL 2026)
Month:
July
Year:
2026
Address:
San Diego, California, USA
Editors:
Yunyao Li, Georg Rehm, Mei Tu
Venue:
ACL
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Publisher:
Association for Computational Linguistics
Note:
Pages:
957–965
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URL:
https://preview.aclanthology.org/ingest-acl/2026.acl-industry.66/
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Cite (ACL):
Egor Maximov, Yulia Kuzkina, Egor Shvetsov, Azamat Kanametov, Aleksandr Prutko, Maxim Zhelnin, and Aleksei Goncharov. 2026. From 2:4 to 8:16 sparsity patterns in LLMs for Outliers and Weights with Variance Correction. In Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (ACL 2026), pages 957–965, San Diego, California, USA. Association for Computational Linguistics.
Cite (Informal):
From 2:4 to 8:16 sparsity patterns in LLMs for Outliers and Weights with Variance Correction (Maximov et al., ACL 2026)
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https://preview.aclanthology.org/ingest-acl/2026.acl-industry.66.pdf