Elon Musk’s xAI launches Grok 4 Fast: Cheaper, quicker, and well, faster

xAI Grok

Just months after Grok 4’s release — and the antisemitic meltdown that put its chatbot in headlines for all the wrong reasons — Elon Musk’s xAI is back with a fresh update. The company has announced Grok 4 Fast, a lighter, quicker reasoning model designed to deliver near-identical performance to Grok 4 while consuming 40% fewer “thinking tokens.”

Faster, cheaper, leaner

xAI claims Grok 4 Fast slashes costs dramatically, offering a 98% price reduction for comparable results on key benchmarks. Whether the task is generating code or fetching answers from the web, the company says users will now get faster, more efficient responses without compromising quality.

Borrowing from rivals

The design mirrors OpenAI’s strategy with GPT-5 — switching between a heavy “reasoning” model for complex queries and a leaner model for rapid replies. Grok 4 Fast is built on a unified architecture that automatically shifts between the two, depending on user needs.

Benchmarks and rollout

On LMArena, a site that pits AI models against each other, Grok 4 Fast took first place in search-related tasks but only managed eighth in text-based evaluations. Still, the update has been rolled out broadly, including to free users across web, iOS and Android apps.

A crowded race

With Anthropic’s Claude Opus 4.1 and Google’s Gemini waiting in the wings for their next upgrades, xAI’s speed-focused update looks like an effort to stay in the race — and move past Grok’s very public missteps.