Claude Sonnet 5 vs Llama 4 (405B)
Head-to-head technical comparison of intelligence, capabilities, and API pricing.
Claude Sonnet 5
Anthropic
AI Mastery Index94
LMSYS Arena1356
Technical (MMLU-Pro)94%
Cost per 1M Tokens$2
Llama 4 (405B)
Meta
AI Mastery Index90.5
LMSYS Arena1285
Technical (MMLU-Pro)90.5%
Cost per 1M Tokens$0
Architect's Verdict
When comparing Claude Sonnet 5 and Llama 4 (405B), Claude Sonnet 5 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.