OpenAI upgrades ChatGPT's default Instant model with better accuracy and personalization
… As per its internal benchmarks, GPT-5.5 Instant produced 52.5% fewer hallucinated claims than GPT-5.3 Instant in medicine, law, and finance. GPT-5.5 Instant also improves performance in image analysis and STEM-related questions, thanks to improvements across visual reasoning, math, and science. …