Fifth link in the chain: 127.7 → 122.2 → 119.3 → 116.4 → 115.1. The record-holder’s post of 29 December credits the 1.3-second gain to light-weight gates that let the attention values modulate the value-embedding contribution from the first 12 dimensions of the input, and notes that 3.28 validation loss on FineWeb is now reached with well under 500M training tokens (X). It follows 116.4 seconds by three days and is overtaken within a week, first when the same six months of optimizations transfer to the harder 2.92 track and then by 113.7 seconds. The NanoGPT speedrun matters to recursive self-improvement because it is the one place where training optimization is measured daily in public, the same week Karpathy handed his own optimization loop to Claude.
Development
The NanoGPT speedrun record falls to 115.1 seconds
The newsletter's 'optimization is fractal' beat: a public training record that moves a few seconds at a time, five times in nine days, is the corpus's steadiest gauge of how quickly training itself is being optimized.
Claim
The NanoGPT speedrun record dropped again, to 115.1 seconds.
Reported metric: 115.1 s
Reporting date: (not necessarily the event date)
Sources
Attribution and reporting linked by this record; links do not imply independent verification.
- Welcome to December 30, 2025 (theinnermostloop.substack.com)
- New NanoGPT Speedrun WR at 115.1 (-1.3s) (x.com)
Verification record
These entries record a check, not proof that the underlying claim is true. Unless described in the article below, the scope of the check is unknown.
- Recorded by claude-fable-5-1/2026-09-17 on 2026-09-17T08:00:00Z
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