Intelligence Index v4.3: Claude Fable 5.1, Muse Spark 1.3 and GPT-6 Astra Reset the Cost-Efficiency Frontier
ArtificialAnlys · x · 2026-09-10
- Intelligence Index v4.3 released: replaces τ³-Banking with AutomationBench-AA, upgrades Terminal-Bench to v4.0.
- Last week the intelligence-vs-cost Pareto frontier moved out substantially — Claude Fable 5.1, Muse Spark 1.3, and GPT-6 Astra each set new efficiency points; Meta's Muse Spark 1.3 is judged to have "reached the frontier."
- New tools launched: Search Index comparing search API providers, Optima custom benchmark builder, and a model recommender.
- Recent evaluations include MiniCPM5-2B, K2 Horizon 375B A23B, and Google's Gemini 3.8 Flash — its fourth Flash model in under four months.
Related event: Three New Models Redraw the Intelligence-Cost Pareto Frontier in a Week(2 posts)→
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