OpenAI GPT-4.5 preview

 Introducing GPT-4.5 | OpenAI

a research preview of GPT‑4.5... largest and best model for chat yet. GPT‑4.5 is a step forward in scaling up pre-training and post-training. By scaling unsupervised learning, GPT‑4.5 improves its ability to recognize patterns, draw connections, and generate creative insights without reasoning.

“It’s a lemon”—OpenAI’s largest AI model ever arrives to mixed reviews - Ars Technica

"The verdict is in: OpenAI's newest and most capable traditional AI model, GPT-4.5, is big, expensive, and slow, providing marginally better performance than GPT-4o at 30x the cost for input and 15x the cost for output. The new model seems to prove that longstanding rumors of diminishing returns in training unsupervised-learning LLMs were correct and that the so-called "scaling laws" cited by many for years have possibly met their natural end." 

Is it?