The power of fine-grained experts: Granularity boosts expressivity in Mixture of Experts

Fuente: arXiv
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Main Authors: Boix-Adsera, Enric, Rigollet, Philippe
Format: Preprint
Published: 2025
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author Boix-Adsera, Enric
Rigollet, Philippe
author_facet Boix-Adsera, Enric
Rigollet, Philippe
contents Mixture-of-Experts (MoE) layers are increasingly central to frontier model architectures. By selectively activating parameters, they reduce computational cost while scaling total parameter count. This paper investigates the impact of the number of active experts, termed granularity, comparing architectures with many (e.g., 8 per layer in DeepSeek) to those with fewer (e.g., 1 per layer in Llama-4 models). We prove an exponential separation in network expressivity based on this design parameter, suggesting that models benefit from higher granularity. Experimental results corroborate our theoretical findings and illustrate this separation.
format Preprint
id arxiv_https___arxiv_org_abs_2505_06839
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle The power of fine-grained experts: Granularity boosts expressivity in Mixture of Experts
Boix-Adsera, Enric
Rigollet, Philippe
Machine Learning
Artificial Intelligence
Mixture-of-Experts (MoE) layers are increasingly central to frontier model architectures. By selectively activating parameters, they reduce computational cost while scaling total parameter count. This paper investigates the impact of the number of active experts, termed granularity, comparing architectures with many (e.g., 8 per layer in DeepSeek) to those with fewer (e.g., 1 per layer in Llama-4 models). We prove an exponential separation in network expressivity based on this design parameter, suggesting that models benefit from higher granularity. Experimental results corroborate our theoretical findings and illustrate this separation.
title The power of fine-grained experts: Granularity boosts expressivity in Mixture of Experts
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2505.06839