“It’s a lemon”—OpenAI’s largest AI model ever arrives to mixed reviews
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.
An AI expert who requested anonymity told Ars Technica, “GPT-4.5 is a lemon!” when comparing its reported performance to its dramatically increased price, while frequent OpenAI critic Gary Marcus called the release a “nothing burger” in a blog post (though to be fair, Marcus also seems to think most of what OpenAI does is overrated).
Former OpenAI researcher Andrej Karpathy wrote on X that GPT-4.5 is better than GPT-4o but in ways that are subtle and difficult to express. “Everything is a little bit better and it’s awesome,” he wrote, “but also not exactly in ways that are trivial to point to.”
