OpenAI unveils GPT-4.5 ‘Orion’, its largest AI model yet

OpenAI Launches GPT-4.5

OpenAI announced on Thursday it is launching GPT-4.5, the much-anticipated AI model code-named Orion. GPT-4.5 is OpenAI’s largest model to date, trained using more computing power and data than any of the company’s previous releases. Despite its size, OpenAI notes in a whitepaper that it does not consider GPT-4.5 to be a frontier model.

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.

Anticipation for Orion

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.

In every GPT generation before GPT-4.5, scaling up led to massive jumps in performance across domains including mathematics, writing, and coding. Indeed, OpenAI says that GPT-4.5’s increased size has given it “a deeper world knowledge” and “higher emotional intelligence.”

Performance of GPT-4.5

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.

“We’re sharing GPT‐4.5 as a research preview to better understand its strengths and limitations,” said OpenAI in a blog post shared with TechCrunch. “We’re still exploring what it’s capable of and are eager to see how people use it in ways we might not have expected.”

Comparison with Other Models

OpenAI emphasizes 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. While GPT-4.5 supports features like file and image uploads and ChatGPT’s canvas tool, it currently lacks capabilities like support for ChatGPT’s realistic two-way voice mode.

In the plus column, GPT-4.5 is more performant than GPT-4o — and many other models besides. 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.

Future of AI Models

OpenAI claims that GPT‐4.5 is “at the frontier of what is possible in unsupervised learning.” That may be true, but the model’s limitations also appear to confirm speculation from experts that pre-training “scaling laws” won’t continue to hold. OpenAI co-founder and former chief scientist Ilya Sutskever said in December that “we’ve achieved peak data,” and that “pre-training as we know it will unquestionably end.”

In response to the pre-training hurdles, the industry — including OpenAI — has embraced reasoning models, which take longer than non-reasoning models to perform tasks but tend to be more consistent. By increasing the amount of time and computing power that AI reasoning models use to “think” through problems, AI labs are confident they can significantly improve models’ capabilities.

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.