Grok 4.6 vs Llama 4 (405B)
Head-to-head technical comparison of intelligence, capabilities, and API pricing.
Grok 4.6
xAI
AI Mastery Index93.8
LMSYS Arena1470
Technical (MMLU-Pro)93.1%
Cost per 1M Tokens$2
Llama 4 (405B)
Meta
AI Mastery Index90.5
LMSYS Arena1440
Technical (MMLU-Pro)90.5%
Cost per 1M Tokens$0
Which should you use?
Grok 4.6 leads on the composite index by 3.3 points (93.8 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 Grok 4.6 when
- Higher composite index — 93.8 against 90.5, a gap of 3.3 points.
- Ahead on Arena Elo by 30 points (1470 vs 1440), which is outside the board's published confidence intervals.
- Stronger on MMLU-Pro: 93.1% 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.
Where these numbers come from
Figures as of 2026-09-07. Arena Elo and pricing are read from the public board and each vendor's own pricing page; see the full leaderboard for all 34 models and which columns are measured rather than estimated, or the benchmark matrix for scores benchmark by benchmark.