OpenAI has introduced GPT-4.5, its most advanced and largest large language model (LLM) to date. The company describes it as its “most knowledgeable model yet,” but clarifies that it is not a breakthrough and may not outperform models like o1 or o3-mini, which excel in reasoning tasks.
GPT-4.5 enhances writing capabilities, expands general knowledge, and offers what OpenAI calls an “improved personality” compared to earlier versions. The model is designed to provide more natural interactions, better pattern recognition, and stronger problem-solving abilities, making it suitable for tasks such as writing, programming, and real-world problem-solving.
Despite these improvements, OpenAI has tempered expectations, emphasizing that GPT-4.5 does not introduce groundbreaking innovations. A leaked OpenAI document states, “GPT-4.5 is not a breakthrough model, but it surpasses GPT-4 in computational efficiency by more than 10 times.” However, it reportedly does not introduce seven new features seen in previous reasoning models and underperforms compared to o1, o3-mini, and Deep Research in most benchmarks.
Training and Performance Insights
OpenAI previously disclosed that it used its reasoning model o1 to train GPT-4.5 on synthetic data. The company stated that the training process involved new supervision techniques, alongside traditional methods like supervised fine-tuning (SFT) and reinforcement learning from human feedback (RLHF), similar to those used for GPT-4o.
Raphael Gontijo Lopes, a researcher at OpenAI, highlighted the model’s refined conversational abilities: “We adapted GPT-4.5 to collaborate better, making conversations warmer, more intuitive, and more emotionally rich.” According to OpenAI’s internal evaluations, human testers found GPT-4.5 to be superior to GPT-4o in nearly every category.
Although limitations remain, OpenAI reports that GPT-4.5 hallucinates significantly less than GPT-4o and slightly less than o1. The model also demonstrates greater intuition and creativity, better understands user intent, and interprets subtle cues with improved nuance.
Availability and Future Prospects
GPT-4.5 is currently available to users with a $200-per-month ChatGPT Pro subscription, as well as researchers, notes NIXsolutions. OpenAI states that the release is part of preliminary research testing to better understand the model’s strengths and limitations. “We’re still learning about its capabilities and are excited to see people use it in ways we might not have expected,” the company said. OpenAI has not yet announced when GPT-4.5 will be available to the general public, but we’ll keep you updated.
Recent reports indicate that OpenAI plans to launch GPT-4.5 by the end of February and GPT-5 by the end of May. CEO Sam Altman described GPT-5 as “a system that combines a lot of our technologies,” confirming that it will include OpenAI’s o3 model. While OpenAI released o3-mini last month, the full o3 model will debut as part of GPT-5. The company’s long-term strategy is to integrate its large language models into a more powerful system capable of autonomously selecting the best resources for problem-solving.