OpenAI releases GPT-4.5 as a research preview
GPT-4.5 released as a research preview — OpenAI’s largest chat model, built by scaling unsupervised learning, available to Pro users and developers
Why it matters
A non-reasoning model that does not think before responding; company-reported GPQA 71.4% and SWE-bench Verified 38.0% trailed o3-mini (high) at 79.7% and 61.0%, while it led on MMMLU (85.1% vs 81.1%) and SWE-Lancer Diamond (32.6% vs 10.8%)
Source — Primary sources first; secondary reports are labelled “Press”
Officialopenai.comhttps://openai.com/index/introducing-gpt-4-5/Added in Week 41, 2026 · See that week