GPT-6 Astra vs GPT-6.1 Sol vs Gemini 4 Argon vs Claude Fable 5.1 compared

Four frontier models shipped within 30 days: Claude Fable 5.1 (Sept 1), GPT-6 Astra (Sept 3), then GPT-6.1 Sol and Gemini 4 Argon in late September. Astra and Fable 5.1 list at $10/$50 per 1M tokens, while Sol and Argon cost one-fifth of that, though Argon is limited to the Fairwind program. Fable 5.1 costs $9.18 per task versus $4.72 for Astra at equal list prices.

• Astra and Fable 5.1: $10 input, $50 output per 1M tokens
• Sol and Argon cost 5x less; Argon limited to Fairwind
• Fable 5.1: $9.18 per task vs $4.72 for Astra
• Fable 5.1 cache read $0.25 vs Astra's $1.00