Backprop-free pretraining hits 4,000x speedup in 10 days, now 1.6 seconds per run

SonglinYang4 · x · 2026-10-30

Zeroth-order optimization is having a breakthrough month: in the 10 days since the Noise speedrun launched, transformer pretraining time fell from 1.76 hours to 1.6 seconds (4,000x). Latest record: 3.5 val loss on FineWeb-30M in 22.7s on one 8xH100 node (down from 123s). Key wins: single-root credit assignment (pairing was pure estimator noise), Gluon Hopper TMA kernels, and fused chain tails keeping 64-move tiles in shared memory to avoid 1GB HBM round trips. Scaling remains the open question—some tricks won't scale, and the team plans dataset scaling tests starting at 30M tokens.

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