GPT-6.1 Sol closes 80% of the no-CoT gap to Astra
An independent rerun shows GPT-6.1 Sol closing most of the no-CoT gap to Astra; the architecture explanation remains the author's own guess, awaiting replication.
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GPT-6.1 Sol, without chain-of-thought, closes 80% of the gap between GPT-6 Sol and GPT-6 Astra across 27 tasks (95% CI: 72–87%) — the result of an independent rerun reported by researcher Rauno Arike on LessWrong, and it sits closer to Astra than to GPT-6 Sol on 24 of 27.
The run follows his earlier no-CoT evaluation of Astra: since 6.1 Sol does not support disabling reasoning, he substituted reasoning_effort=low with an immediate-recall system prompt, took k=1 sample per question, and excluded nine tasks that previously failed to separate the older models. Time-horizon estimates moved from 4.0 minutes for GPT-6 Sol to 35 minutes, though the author himself flags that most benchmarks saturate, making those estimates highly uncertain.
His looped-transformer explanation rests on a gpt-6-astra-minor registry path spotted in Azure's playground configuration and community speculation; OpenAI has not confirmed it.