On the heels of Anthropic rolling out Claude 3.7 Sonnet, OpenAI has announced a research preview of GPT-4.5, which is available to Pro users and developers.

According to OpenAI, GPT-4.5 is its “largest and best model for chat yet.” The new model improves pattern recognition, better creative insights without reasoning, and its ability to draw connections. The company says it has scaled both unsupervised learning and reasoning.

• Scaling reasoning⁠ teaches models to think and produce a chain of thought before they respond, allowing them to tackle complex STEM or logic problems. Models like OpenAI o1 and OpenAI o3‑mini advance this paradigm.
• Unsupervised learning, on the other hand, increases world model accuracy and intuition.

The improvements to reasoning and unsupervised learning lead to more natural interactions.

Early testing shows that interacting with GPT‑4.5 feels more natural. Its broader knowledge base, improved ability to follow user intent, and greater “EQ” make it useful for tasks like improving writing, programming, and solving practical problems. We also expect it to hallucinate less.

Combining deep understanding of the world with improved collaboration results in a model that integrates ideas naturally in warm and intuitive conversations that are more attuned to human collaboration. GPT‑4.5 has a better understanding of what humans mean and interprets subtle cues or implicit expectations with greater nuance and “EQ”. GPT‑4.5 also shows stronger aesthetic intuition and creativity. It excels at helping with writing and design.

OpenAI makes clear that GPT-4.5 is not a reasoning model, although it will lay the groundwork for more advanced reasoning models in the future.

GPT‑4.5 doesn’t think before it responds, which makes its strengths particularly different from reasoning models like OpenAI o1. Compared to OpenAI o1 and OpenAI o3‑mini, GPT‑4.5 is a more general-purpose, innately smarter model. We believe reasoning will be a core capability of future models, and that the two approaches to scaling—pre-training and reasoning—will complement each other. As models like GPT‑4.5 become smarter and more knowledgeable through pre-training, they will serve as an even stronger foundation for reasoning and tool-using agents.

As stated, GPT-4.5 is only available to Pro users, at $200 a month, as well as developers.

Compared to Claude 3.7 Sonnet

Given the timing of OpenAI’s announcement, and the fact that GPT 4.5 is still a research preview with limited availability, it seems likely the announcement was as much about responding to Anthropic’s release of CLaude 3.7 Sonnet as anything else.

It’s also interesting that, for all its advances, GPT-4.5 still still not a reasoning model. In contrast, Claude 3.7 Sonnet takes the approach of combining ordinary LLM capabilities and reasoning abilities all in one model, as the company made clear in its announcement.

We’ve developed Claude 3.7 Sonnet with a different philosophy from other reasoning models on the market. Just as humans use a single brain for both quick responses and deep reflection, we believe reasoning should be an integrated capability of frontier models rather than a separate model entirely. This unified approach also creates a more seamless experience for users.

Claude 3.7 Sonnet embodies this philosophy in several ways. First, Claude 3.7 Sonnet is both an ordinary LLM and a reasoning model in one: you can pick when you want the model to answer normally and when you want it to think longer before answering. In the standard mode, Claude 3.7 Sonnet represents an upgraded version of Claude 3.5 Sonnet. In extended thinking mode, it self-reflects before answering, which improves its performance on math, physics, instruction-following, coding, and many other tasks. We generally find that prompting for the model works similarly in both modes.

OpenAI has long-since lost its position as the undisputed leader in the AI industry, with Anthropic, Google, and now DeepSeek, providing real competition. In many ways, OpenAI’s GPT-4.5 announcement seems like an effort to recapture attention on the heels of being upstaged by a competitor’s announcement.