IMU-1: Sample-Efficient Pre-training of Small Language Models

George Grigorev

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arXiv · 2602.02522

IMU-1: Sample-Efficient Pre-training of Small Language Models

George Grigorev

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Abstract

We present IMU-1, a 430M-parameter language model trained on 72B tokens that approaches the benchmark performance of models trained on 56x more data. We describe a validated training recipe combining recent architectural interventions (QK-norm attention, per-head gating, value residuals, LayerNorm scaling) with optimization advances (NorMuon with cautious weight decay, muP parametrization) and a three-stage training schedule with post-hoc checkpoint EMA. We provide ablations for each component and release code, weights and data to enable reproduction: https://huggingface.co/thepowerfuldeez/imu1_base

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George Grigorev. 2026-01-25. IMU-1: Sample-Efficient Pre-training of Small Language Models. https://arxiv.org/abs/2602.02522

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