Elon Musk released the newest artificial intelligence model from his company xAI on Wednesday night. In an hour-long public reveal session, he called the model, Grok 4, “the smartest AI in the world” and claimed it was capable of getting perfect SAT scores and near-perfect GRE results in every subject, from the humanities to the sciences.
During the online launch, Musk and members of his team described testing Grok 4 on a metric called Humanity’s Last Exam (HLE)—a 2,500-question benchmark designed to evaluate an AI’s academic knowledge and reasoning skill. Created by nearly 1,000 human experts across more than 100 disciplines and released in January 2025, the test spans topics from the classics to quantum chemistry and mixes text with images. Grok 4 reportedly scored 25.4 percent on its own. But given access to tools (such as external aids for code execution or Web searches), it hit 38.6 percent. That jumped to 44.4 percent with a version called Grok 4 Heavy, which uses multiple AI agents to solve problems. The two next best-performing AI models are Google’s Gemini-Pro (which achieved 26.9 percent with the tools) and OpenAI’s o3 model (which got 24.9 percent, also with the tools). The results from xAI’s internal testing have yet to appear on the leaderboard for HLE, however, and it remains unclear whether this is because xAI has yet to submit the results or because those results are pending review. Manifold, a social prediction market platform where users bet play money (called “Mana”) on future events in politics, technology and other subjects, predicted a 1 percent chance, as of Friday morning, that Grok 4 would debut on HLE’s leaderboard with a 45 percent score or greater on the exam within a month of its release. (Meanwhile xAI has claimed a score of only 44.4.)
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