GPT-6 Astra vs Llama 4 (405B)

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

GPT-6 Astra
OpenAI
AI Mastery Index96.7
LMSYS Arena1496
Technical (MMLU-Pro)95.8%
Cost per 1M Tokens$10
Llama 4 (405B)
Meta
AI Mastery Index90.5
LMSYS Arena1440
Technical (MMLU-Pro)90.5%
Cost per 1M Tokens$0

Which should you use?

GPT-6 Astra leads on the composite index by 6.2 points (96.7 vs 90.5).

Only Llama 4 (405B) ships open weights, which decides it outright if the workload has to run on your own hardware.

Pick GPT-6 Astra when

  • Higher composite index — 96.7 against 90.5, a gap of 6.2 points.
  • Ahead on Arena Elo by 56 points (1496 vs 1440), which is outside the board's published confidence intervals.
  • Stronger on MMLU-Pro: 95.8% against 90.5%.

Pick Llama 4 (405B) when

  • Open weights, so it is the only one of the two you can run on your own hardware or keep data entirely in-house.

Our reporting on OpenAI and Meta