The Hidden Power of Scaling Factor in LoRA Optimization
- URL: http://arxiv.org/abs/2606.12883v1
- Date: Thu, 11 Jun 2026 04:19:32 GMT
- Title: The Hidden Power of Scaling Factor in LoRA Optimization
- Abstract summary: In Low-Rank Adaptation (LoRA), the scaling factor $$ is often treated as a mere complement to the learning rate.<n>We show that $$ is the dominant driver of effective optimization, delivering gains that cannot be replicated by learning rate scaling alone.<n>We propose LoRA-$$, a minimalist framework that restores $$ to its principled regime, making LoRA compatible with standard small learning rates.
- Score: 30.400211119439486
- License: http://creativecommons.org/licenses/by/4.0/
- Abstract: In Low-Rank Adaptation (LoRA), the scaling factor $α$ is often treated as a mere complement to the learning rate, yet its role in optimization remains poorly understood. In this paper, we reveal that the scaling factor $α$ and the learning rate function differently, with $α$ emerging as the dominant driver of effective optimization, delivering gains that cannot be replicated by learning rate scaling alone. Through the synergy of extensive empirical analysis and a theoretical Signal-Drift framework, we uncover three findings into LoRA's scaling mechanism: First, LoRA's spectral suppression smooths the optimization landscape, rendering standard hyperparameters overly conservative and creating an optimization gap. Second, when leveraging this smoothness to accelerate convergence, $α$ outperforms the learning rate by amplifying the task signal without increasing the drift ratio. Third, the optimal scaling factor follows a sublinear relationship with the rank, well characterized by a square-root law with an unexpectedly large coefficient, revealing the insufficient scaling of existing rank-tied heuristics. Based on these insights, we propose LoRA-$α$, a minimalist framework that restores $α$ to its principled regime, making LoRA compatible with standard small learning rates. Extensive evaluations across diverse tasks demonstrate that LoRA-$α$ consistently improves performance while streamlining hyperparameter search, unleashing the learning potential of LoRA.
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