Grok-2 vs Gemini 3.1 Ultra

Head-to-head technical comparison of intelligence, capabilities, and API pricing.

Grok-2

xAI

AI Mastery Index84.5

LMSYS Arena1260

Technical (MMLU-Pro)87.5%

Cost per 1M Tokens$5

Gemini 3.1 Ultra

Google

AI Mastery Index92.5

LMSYS Arena1320

Technical (MMLU-Pro)92.5%

Cost per 1M Tokens$20

Architect's Verdict

When comparing Grok-2 and Gemini 3.1 Ultra, Gemini 3.1 Ultra edges out in overall capabilities according to the AI Mastery Index. However, for cost-sensitive workloads, Grok-2 offers a more economical API at $5 per 1M tokens. Your choice should depend heavily on whether you prioritize raw reasoning (MMLU) or scalable deployment economics.