After weeks of waiting, OpenAI has finally introduced GPT-4.5, its latest and largest AI language model. It was internally referred to as Orion.
It is in research preview for ChatGPT Pro users, offering better writing, knowledge, and a more natural, less hallucinatory experience. GPT-4.5 is first being made available to ChatGPT Pro users, with Plus and Team users gaining access next week, followed by Enterprise and Education users.
“GPT-4.5 is ready,” posted OpenAI CEO Sam Altman on X. “It is a giant, expensive model. We really wanted to launch it to plus and pro at the same time, but we’ve been growing a lot and are out of GPUs.”
Altman announced that tens of thousands of GPUs will be added next week for the Plus tier, with hundreds of thousands more coming soon, all of which are expected to be fully utilised.
In the recent NVIDIA earnings call, CEO Jensen Huang said the company’s inference demand is accelerating, fuelled by test-time scaling and new reasoning models.
“Models like OpenAI’s, Grok 3, and DeepSeek R1 are reasoning models that apply inference-time scaling. Reasoning models can consume 100 times more compute,” he said.
GPT4.5 was only trained with pretraining, supervised finetuning, and RLHF, so this is not a reasoning model. It is an extension of the GPT series of models, unlike the o series of models.
According to the website, the pricing for input tokens is $75.00 per million tokens, while cached input tokens are available at a reduced rate of $37.50 per million tokens. The cost for output tokens is $150.00 per million tokens.
“This isn’t a reasoning model and won’t crush benchmarks. It’s a different kind of intelligence and there’s a magic to it I haven’t felt before.” added Alman.
The model is more computationally efficient, and offers a tenfold improvement over GPT-4.
In the livestream, the OpenAI team outlined the evolution of GPT models – from GPT-1 was barely coherent, to GPT-3.5 became the first truly useful model, to GPT-4.5 continuing this trend with incremental enhancements.
Recently, Anthropic released its Claude Sonnet 3.7 and xAI launched its Grok 3, competing in the same space.
Altman had previously announced the roadmap for GPT-5. OpenAI’s goal is to combine its large language models to eventually create a more capable model that could be labeled as artificial general intelligence, or AGI.
