Grok 3, released February 17, 2025 alongside Grok 3 mini, was trained on Colossus — xAI's Memphis supercomputer of around 200,000 GPUs — with roughly ten times the compute of Grok 2. It introduced Think mode for step-by-step reasoning and DeepSearch, an agentic research tool that scans the web and X in real time.

The release put xAI on the frontier map barely two years after the company's founding, with launch benchmarks competitive with o1 and Gemini 2.0 across math, science, and coding. It headlined xAI's lineup for five months until Grok 4 arrived in July 2025.