OpenAI o3 vs Llama 3.1 405B

Compare OpenAI o3 by OpenAI against Llama 3.1 405B by Meta AI, tested across 7 shared challenges. Updated March 2026.

Which is better, OpenAI o3 or Llama 3.1 405B?

OpenAI o3 and Llama 3.1 405B are both competitive models. OpenAI o3 costs $10/M input tokens vs $2.7/M for Llama 3.1 405B. Compare their real outputs side by side below.

Key Differences Between OpenAI o3 and Llama 3.1 405B

OpenAI o3 is made by openai while Llama 3.1 405B is from meta. On pricing, OpenAI o3 costs $10/M input tokens vs $2.7/M for Llama 3.1 405B.

Our Verdict
OpenAI o3
OpenAI o3
Llama 3.1 405B
Llama 3.1 405B

No community votes yet. On paper, these are closely matched - try both with your actual task to see which fits your workflow.

Llama 3.1 405B is 13x cheaper per token — worth considering if cost matters.

Too close to call
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OpenAI o3Llama 3.1 405B
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