Sam Altman’s OpenAI launches GPT-4.5 with fewer ‘hallucinations’ as AI race heats up
Sam Altman’s OpenAI released GPT-4.5, an upgraded version of the artificial intelligence model that powers ChatGPT, to select users on Thursday as it looks to stave off challenges from rivals like Elon Musk’s xAI.
Described as OpenAI’s “largest and best model for chat yet,” GPT-4.5 was initially made available as a “research preview” for a limited number of software developers and for ChatGPT Pro subscribers, the San Francisco-based startup said in a blog post.
GPT-4.5 is less prone to so-called “hallucinations” – a phenomenon where AI models fabricate false responses to user prompts. OpenAI said the upgraded model has a hallucination rate of just 37.1%, down from 61.8% from the last version.
“Early testing shows that interacting with GPT‑4.5 feels more natural,” OpenAI said in a blog post. “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.”
Altman described GPT-4.5 as “the first model that feels like talking to a thoughtful person to me” – but also tried to temper expectations about the launch.
He admitted that the update was a “giant, expensive model” that “won’t crush benchmarks.”
Microsoft-backed OpenAI has faced increasingly stiff competition from a host of rivals, ranging from Google’s Gemini AI to xAI’s Grok and China-based DeepSeek.
ChatGPT remains the world’s leading chatbot service with more than 400 million weekly active users.
Earlier this month, Musk unveiled the Grok 3 model, which scored higher on tests in math, science and coding than OpenAI’s GPT-4o, Google’s Gemini, Anthropic’s Claude and DeepSeek’s V3 models.
The battle between Musk and Altman has also extended to federal court. Musk has filed an antitrust lawsuit against OpenAI and has sought an injunction to block Altman’s plans to transform the startup to a for-profit entity.
Musk cofounded OpenAI alongside Altman, but left the startup after disagreements about its long-term plans. The two billionaires have since become bitter rivals and frequently trade public insults.
Elsewhere, Mark Zuckerberg’s Meta announced this week that it will launch a standalone app for its own AI chatbot that will directly compete with ChatGPT.
In response to that announcement, Altman joked that OpenAI could challenge the Facebook and Instagram parent on its own turf.
“Ok fine maybe we’ll do a social app,” Altman wrote on X. “Lol if facebook tries to come at us and we just uno reverse them it would be so funny.”
