Opus 4.8 Fails Evaluation

ezyang · x · 2026-07-17

Opus 4.8 failed a specific evaluation. The test required "downscaling" a large LLM training setup to a single GPU scenario: retaining the local compute kernel of a single rank while mocking all data typically received from communication, then checking if the model could maintain a non-NaN loss after 10 steps. The author concluded that Opus 4.8 failed this test.

Related event: Opus 4.8 Fails Single-GPU Distributed Communication Challenge(2 posts)→

Original post →

More from Models

Models channel →