GPT-5.6 Terra vs Llama 4 (405B)
Head-to-head technical comparison of intelligence, capabilities, and API pricing.
GPT-5.6 Terra
OpenAI
AI Mastery Index93.9
LMSYS Arena1470
Technical (MMLU-Pro)93.5%
Cost per 1M Tokens$2.5
Llama 4 (405B)
Meta
AI Mastery Index90.5
LMSYS Arena1440
Technical (MMLU-Pro)90.5%
Cost per 1M Tokens$0
Architect's Verdict
When comparing GPT-5.6 Terra and Llama 4 (405B), GPT-5.6 Terra edges out in overall capabilities according to the AI Mastery Index. However, for cost-sensitive workloads, Llama 4 (405B) offers a more economical API at $0 per 1M tokens. Your choice should depend heavily on whether you prioritize raw reasoning (MMLU) or scalable deployment economics.