Introducing GPT-4.5

OpenAI released GPT-4.5 as a research preview on February 27, 2025 for Pro users and developers worldwide. The post calls it the largest and strongest GPT model for chat, with lower hallucination and better steerability, but the excerpt does not disclose the SimpleQA scores or hallucination-rate values. The key detail is the training path: scaled unsupervised learning on Microsoft Azure AI supercomputers, plus new techniques using data derived from smaller models.

Why it matters: A major OpenAI model launch is same-day coverage by default: the post confirms a GPT-4.5 research preview for Pro users and developers worldwide, so HKR-H/K/R all pass. It stays below 95 because the excerpt does not disclose key benchmarks, pricing, or context-window details.