Paper claims LM head destroys 95-99% of training signal in backpropagation

LChoshen · x · 2026-08-17

A new paper titled "Lost in Backpropagation: The LM Head is a Gradient Bottleneck" argues that the output layer of LLMs destroys 95-99% of the training signal during backpropagation, significantly slowing down pretraining. The author discusses how a network without this bottleneck might function.

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