xAI Ships Grok 3 — Trained on 200,000 GPUs at the Colossus Data Center

xAI released Grok 3 on February 17, 2025, after training with approximately 200,000 GPUs at the Colossus data center — representing 10x more compute than Grok 2. A smaller Grok 3 mini shipped alongside it, according to xAI.

Raw Compute Power

Colossus is xAI's custom-built data center, and Grok 3 represents its full capability. 10x more compute than Grok 2 is a brute-force approach to model improvement: pour more resources into training and see what emerges. In this case, it produced a model that outperformed GPT-4o on AIME (math) and GPQA (PhD-level science) benchmarks.

Think and Big Brain Modes

Grok 3 introduced two reasoning modes:

• Think: Standard chain-of-thought reasoning, comparable to OpenAI's o1
• Big Brain: More compute-intensive reasoning for the hardest problems

Big Brain mode dedicates significantly more inference-time compute to each response, trading speed for depth. It's xAI's version of what OpenAI does with o3-pro and what Claude does with extended thinking at max effort.

X Integration

Grok 3 is deeply integrated with the X (Twitter) platform, giving it real-time access to public posts, trends, and discourse. This creates a unique data advantage — no other model has live access to social media at this scale.

Initially available only to Premium+ and SuperGrok subscribers, Grok 3 briefly became free on February 20 before returning to paid access. The X Premium+ subscription price rose from $22 to $40/month alongside the launch.

Where Grok 3 Stands

At launch, Grok 3 was competitive on math and science benchmarks but lagged behind Claude on coding and GPT-4o on general knowledge. Its primary differentiator is the X data integration and xAI's willingness to apply significantly less content filtering than competitors.

Our Take

Grok 3 is xAI's first model that demands attention from competitors. The 200,000 GPU training run shows xAI has the compute infrastructure to compete at the frontier. The X data integration is a genuine differentiator — live social media context is something no other model can offer. Whether that advantage translates to sustained competitive position depends on whether xAI can match the rapid iteration cadence of OpenAI and Anthropic, which ship major updates every few weeks.

FAQ

What is Grok 3? Grok 3 is xAI's flagship AI model released February 17, 2025, trained with 10x more compute than Grok 2 using approximately 200,000 GPUs at the Colossus data center.

What is Big Brain mode? Big Brain mode is Grok 3's enhanced reasoning mode that applies more compute-intensive thinking to harder problems, similar to OpenAI's o3-pro or Claude's extended thinking at max effort.

How much does Grok cost? Grok 3 requires an X Premium+ subscription at $40/month or a SuperGrok subscription. API access is available through the xAI Enterprise API.

Does Grok have access to X/Twitter data? Yes, Grok is deeply integrated with the X platform, giving it real-time access to public posts, trends, and social discourse — a unique data advantage no competitor has.