Llama 4 (405B) vs GPT-5.6 Sol
Head-to-head technical comparison of intelligence, capabilities, and API pricing.
Llama 4 (405B)
Meta
AI Mastery Index90.5
LMSYS Arena1440
Technical (MMLU-Pro)90.5%
Cost per 1M Tokens$0
GPT-5.6 Sol
OpenAI
AI Mastery Index95.7
LMSYS Arena1485
Technical (MMLU-Pro)95.1%
Cost per 1M Tokens$5
Architect's Verdict
When comparing Llama 4 (405B) and GPT-5.6 Sol, GPT-5.6 Sol 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.