OpenAI GPT-5.5 Instant default model
Key Questions
What is GPT-5.5 Instant?
GPT-5.5 Instant is OpenAI's new default model on ChatGPT. It focuses on reduced hallucinations and improved performance across math and multimodal tasks.
What performance improvements does GPT-5.5 Instant offer?
It reports hallucination reduction to 52.5%, an AIME score of 81.2, and MMMU-Pro score of 76. These metrics position it as a strong general-purpose model.
What new feature comes with GPT-5.5 Instant?
The release includes a memory sources feature for enhanced personalization. It builds on prior capabilities with Codex integration for computer control tasks.
OpenAI releases GPT-5.5 Instant as new default on ChatGPT with hallucination reduction (52.5%), AIME 81.2, MMMU-Pro 76. Includes memory sources feature for personalization.
Sources (2)
Updated May 24, 2026