GPT-5.5 tops benchmarks but still hallucinates frequently and costs 20 percent more over the API

THE DECODER / 4/25/2026

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Key Points

  • GPT-5.5 has regained the top position on widely used AI benchmarks for OpenAI.
  • Despite improved benchmark performance, GPT-5.5 still hallucinates frequently, indicating reliability issues remain.
  • OpenAI raised the API price, with GPT-5.5 costing about 20% more than before.
  • Even with higher cost and persistent hallucinations, GPT-5.5 is positioned as the best value-for-money option among proprietary models.

GPT-5.5 pushes OpenAI back to the top of the AI benchmarks. The price went up, but it still looks like the best bang for your buck among proprietary models.

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