GPT-6 Astra vs Claude Fable 5.1: Benchmark Lead, Production Dead Heat

It-zubair-huss · reddit · 2026-09-07

A developer compares GPT-6 Astra and Claude Fable 5.1 (same price, same 1M context): Astra leads on FrontierMath Tier 4 (97.6% vs 87.8%), AutomationBench (41.4% vs 31.4%), and BenchCAD (95.9% vs 84.3%); Terminal-Bench 4.0 is a tie and Code Arena WebDev differs by only 35 Elo. Fable 5.1 wins OSWorld 2.0 at 77.9%. Advice: benchmarks don't predict production behavior — test prompts on your own stack before migrating.

Related event: Claude Fable 5.1 and GPT-6 Astra Launch 48 Hours Apart at Identical Prices(9 posts)→

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