xAI’s Grok-4 Heavy challenges OpenAI’s GPT-5, reigniting the battle for AI supremacy
Elon Musk has once again stirred the pot in the global AI race, openly challenging the capabilities of OpenAI’s newly launched GPT-5 model. In a bold statement posted on X (formerly Twitter), the CEO of Tesla and founder of AI startup xAI claimed that his company’s AI model “Grok-4 Heavy” had already outperformed GPT-5 two weeks ago.
“Bottom line: Grok-4 Heavy was smarter than GPT-5 two weeks ago and is now significantly better,” Musk wrote shortly after OpenAI’s announcement of GPT-5 on August 7 (local time). His post included a chart shared by another X user comparing the performance of the two companies’ models, placing GPT-5 somewhere between Grok-4 and Grok-4 Heavy in capability.
Grok-4, launched in early July, is xAI’s latest AI model, and Grok-4 Heavy is an advanced version with multi-agent functionality. Musk also posted a series of images and videos generated by Grok and encouraged users to share their own AI-generated creations using xAI’s tool—likely an effort to showcase the model’s real-world capabilities and boost public engagement.
Meanwhile, OpenAI CEO Sam Altman described GPT-5 as a “major step toward Artificial General Intelligence (AGI)” during a pre-launch briefing. “If GPT-3 felt like talking to a high school student, GPT-4 like a college student, then GPT-5 feels like talking to a PhD-level expert,” Altman said.
The rivalry between Musk and Altman is well known in tech circles. Once co-founders of OpenAI, the two parted ways years ago, with Musk later accusing the company of abandoning its non-profit roots in favor of commercial interests. He has since launched xAI with the goal of building an AI chatbot that surpasses ChatGPT.
Musk even filed a lawsuit against Altman and OpenAI last year, claiming they violated their original agreements by prioritizing profit and striking deals with investors.
As AI becomes increasingly embedded in sectors ranging from defense to creative industries, the competition between tech giants like xAI and OpenAI is more than a race for market dominance—it’s a battle over the future of intelligence itself. With each new release, the bar is raised higher, and the implications for society, ethics, and innovation continue to expand.