OpenAI has announced the launch of GPT-4.5, a massive AI model code-named Orion, which is the company's largest model to date, trained using more computing power and data than any of its previous releases. Despite its size, OpenAI notes that it does not consider GPT-4.5 to be a frontier model, and its performance is mixed, with both impressive and underwhelming results in various benchmarks.

Subscribers to ChatGPT Pro, OpenAI's $200-a-month plan, will gain access to GPT-4.5 in ChatGPT starting Thursday as part of a research preview. Developers on paid tiers of OpenAI's API will also be able to use GPT-4.5 starting today. As for other ChatGPT users, customers signed up for ChatGPT Plus and ChatGPT Team should get the model sometime next week, an OpenAI spokesperson told TechCrunch.

The industry has held its collective breath for Orion, which some consider to be a bellwether for the viability of traditional AI training approaches. GPT-4.5 was developed using the same key technique – dramatically increasing the amount of computing power and data during a "pre-training" phase called unsupervised learning — that OpenAI used to develop GPT-4, GPT-3, GPT-2, and GPT-1. However, there are signs that the gains from scaling up data and computing are beginning to level off.

On several AI benchmarks, GPT-4.5 falls short of newer AI "reasoning" models from Chinese AI company DeepSeek, Anthropic, and OpenAI itself. GPT-4.5 is also very expensive to run, OpenAI admits — so expensive that the company says it's evaluating whether to continue serving GPT-4.5 in its API in the long term.

Despite its limitations, GPT-4.5 has shown impressive performance in certain areas. On OpenAI's SimpleQA benchmark, which tests AI models on straightforward, factual questions, GPT-4.5 outperforms GPT-4o and OpenAI's reasoning models, o1 and o3-mini, in terms of accuracy. According to OpenAI, GPT-4.5 hallucinates less frequently than most models, which in theory means it should be less likely to make stuff up.

In other areas, GPT-4.5 matches or bests leading non-reasoning models, suggesting that the model performs well on math- and science-related problems. OpenAI also claims that GPT-4.5 is qualitatively superior to other models in areas that benchmarks don't capture well, like the ability to understand human intent. GPT-4.5 responds in a warmer and more natural tone, OpenAI says, and performs well on creative tasks such as writing and design.

In informal tests, GPT-4.5 has shown impressive results, such as creating a unicorn in SVG format and responding to a prompt about failing a test in a socially appropriate way. However, these results are not necessarily reflected in academic benchmarks, which has led OpenAI to emphasize that GPT-4.5 is not meant to be a drop-in replacement for GPT-4o, the company's workhorse model that powers most of its API and ChatGPT.

The limitations of GPT-4.5 have sparked debate on the viability of traditional AI training approaches. OpenAI co-founder and former chief scientist Ilya Sutskever has said that "we've achieved peak data," and that "pre-training as we know it will unquestionably end." The industry, including OpenAI, has begun to shift towards reasoning models, which take longer than non-reasoning models to perform tasks but tend to be more consistent.

OpenAI plans to eventually combine its GPT series of models with its o reasoning series, beginning with GPT-5 later this year. GPT-4.5, which reportedly was incredibly expensive to train, delayed several times, and failed to meet internal expectations, may not take the AI benchmark crown on its own. But OpenAI likely sees it as a stepping stone toward something far more powerful.

The launch of GPT-4.5 marks an important milestone in the development of AI, and its mixed performance has significant implications for the industry. As AI continues to evolve, it remains to be seen whether traditional training approaches will continue to be viable, or if new methods will emerge to take their place.