ChatGPT-4.5 is Here: What You Need to Know About OpenAI’s New AI Model

Just moments ago, the highly anticipated ChatGPT-4.5 has officially arrived!
While it is not an advanced reasoning model, OpenAI describes it as more practical and fundamentally more intelligent.

This AI system, dubbed “the most knowledge-rich model to date,” will first be made available as a research preview for Pro users and developers. However, OpenAI has explicitly stated that this is not a cutting-edge architecture upgrade, and in some scenarios, it may not perform as well as top-tier models like o1 or o3-mini.

In simple terms: GPT-4.5 knows more, while the o1 series thinks better.

Key Highlights:

• Expanded Knowledge Base – It has learned significantly more information, making it more knowledgeable than ever.
• Reduced Hallucinations – Fewer instances of AI fabricating facts.
• Higher Emotional Intelligence (EQ) – Better understanding of user intent and emotions.
• More Natural Conversations – Feels more like talking to a human rather than a machine.
• Enhanced Creativity – Performs better in writing and design tasks.

Starting today, ChatGPT Pro users ($200/month) can access the research preview of GPT-4.5. Next week, it will roll out to Plus and Team users, followed by Enterprise and Edu users in the following week.

Capabilities & Limitations

GPT-4.5 can access real-time information, supports web search, file and image uploads, and allows text and code editing via the canvas feature. However, it does not support multimodal features such as voice mode, video, or screen sharing in ChatGPT.

Additionally, OpenAI has introduced GPT-4.5 in the Chat Completions API, Assistants API, and Batch API, allowing all paid developer tiers to preview it. Key features include function calling, structured outputs, streaming, and system messages. The model also supports vision capabilities through image inputs.

However, OpenAI emphasizes that GPT-4.5 is a large and computationally intensive model with a higher operational cost than GPT-4o, and it is not a replacement for GPT-4o.

Breakthroughs in Pretraining and Post-Training

GPT-4.5 has made significant advancements in pretraining and post-training by scaling up unsupervised learning. This has enhanced its ability to recognize patterns, establish connections, and generate creative insights—all without explicit reasoning.

Early testing indicates that user interactions with GPT-4.5 feel more natural, thanks to its broader knowledge base, improved intent recognition, and higher EQ. It excels in writing, coding, and practical problem-solving, and OpenAI expects it to generate even fewer hallucinations—possibly even fewer than the o1 model.

Performance in SimpleQA Benchmark

In the SimpleQA (basic Q&A) test, GPT-4.5 demonstrated high accuracy and a reduced hallucination rate.

Sam Altman’s Roadmap: GPT-4.5 Now, GPT-5 by May

According to Sam Altman, OpenAI plans to launch GPT-5 by the end of May 2025.

GPT-5 has been described as “a system integrating many of OpenAI’s latest technologies” and will include the o3 reasoning model, which was first teased during OpenAI’s “12 Days of Christmas” event in December.

Previously, OpenAI released o3-mini, but the full o3 model will only be part of GPT-5, aligning with OpenAI’s goal of consolidating its language models into a more advanced system—potentially leading toward Artificial General Intelligence (AGI).

Unsupervised Learning vs. Reasoning: Two Paths to Intelligence

OpenAI is enhancing AI capabilities by expanding two complementary paradigms: unsupervised learning and reasoning—each representing a distinct dimension of intelligence.

• Reasoning Expansion – Enables AI to think before responding, forming a chain of thought to tackle complex STEM and logic problems (represented by models like o1 and o3-mini).
• Unsupervised Learning Expansion – Improves the AI’s accuracy and intuition about the world.

For instance, when asked “What was the first language?”, GPT-4.5 responds with:
“We do not fully know what the first language was,” and presents various scholarly perspectives—showcasing its balanced and nuanced approach to answering.

By scaling computation, data, and architectural optimizations, GPT-4.5 has expanded its unsupervised learning, resulting in a deeper understanding of the world, fewer hallucinations, and greater reliability across a broad range of topics.

More Human-Like Conversations

As OpenAI researchers scale models and tackle more complex challenges, teaching AI to better understand human needs and intent is becoming increasingly critical.

For GPT-4.5, researchers developed new scalable techniques that leverage data from smaller models to train larger, more powerful ones. These innovations have improved GPT-4.5’s controllability, nuanced understanding, and natural conversation abilities.

Higher Win Rate in Creativity, Professional Queries, and Everyday Questions

In head-to-head tests with human evaluators, GPT-4.5 consistently outperformed previous models in:

• Creative intelligence
• Professional-level queries
• Everyday conversational tasks

More Human-Like Responses

OpenAI showcased GPT-4.5’s responses compared to GPT-4o on three sample questions:

1. “I failed my exam, and I feel terrible.”

• GPT-4.5 provided a more empathetic response, acknowledging emotions before offering guidance.
• GPT-4o, on the other hand, jumped straight to solutions, making it feel more robotic.

1. “What are your thoughts on space exploration?”

• GPT-4.5 responded more like a human, offering its own opinions and insights.
• GPT-4o relied too heavily on citing sources, making it overly academic and rigid.

The Future: Reasoning as the Core of AI

Unlike OpenAI’s o1 and o3-mini, GPT-4.5 does not inherently engage in advanced reasoning before responding. This makes it more general-purpose and knowledge-driven, while o1 and o3-mini focus on deep reasoning tasks.

OpenAI believes that reasoning will be the core capability of future AI models and that pretraining and reasoning will complement each other. As models like GPT-4.5 become smarter and more knowledgeable, they will serve as stronger foundations for reasoning-based AI agents.

Advancements in AI Lead to Greater Safety

With every AI capability upgrade comes an opportunity to enhance safety.

GPT-4.5 utilizes a new supervised fine-tuning (SFT) and reinforcement learning from human feedback (RLHF) approach, similar to GPT-4o. OpenAI hopes these efforts will lay the groundwork for aligning even more powerful future models.

To ensure its safety, GPT-4.5 underwent rigorous testing using OpenAI’s deployment readiness framework. The results suggest that scaling the GPT paradigm improves AI capabilities across multiple evaluation metrics.

Final Thoughts

GPT-4.5 represents a significant step forward in knowledge retention, emotional intelligence, and conversational naturalness, while OpenAI continues pushing toward GPT-5 and beyond.

Would you like more insights into how GPT-4.5 compares with previous models? 🚀