Old Zhang's AI Learning

Oct 6, 2026 · Industry Insights

Codex Declines: SemiAnalysis Reveals Claude Opus 5.5 Delivers 5x Value Over OpenAI

The article analyzes OpenAI's Codex decline, citing a SemiAnalysis report showing Anthropic's Claude Opus 5.5 provides over 5x more API value per dollar than OpenAI, with benchmarks comparing GPT-6.1 Sol, Gemini 3.8 Flash, and Claude Opus 5.5 on throughput and task completion, explaining how slow models disrupt developer flow.