GPT-5.6 Sol vs Grok 4.5

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

GPT-5.6 Sol

OpenAI

AI Mastery Index95.7

LMSYS Arena1485

Technical (MMLU-Pro)95.1%

Cost per 1M Tokens$5

Grok 4.5

xAI

AI Mastery Index93.4

LMSYS Arena1465

Technical (MMLU-Pro)92.8%

Cost per 1M Tokens$2

Architect's Verdict

When comparing GPT-5.6 Sol and Grok 4.5, GPT-5.6 Sol edges out in overall capabilities according to the AI Mastery Index. However, for cost-sensitive workloads, Grok 4.5 offers a more economical API at $2 per 1M tokens. Your choice should depend heavily on whether you prioritize raw reasoning (MMLU) or scalable deployment economics.