GPT-5.3-Codex vs Llama 3.1 405B
Compare GPT-5.3-Codex by OpenAI against Llama 3.1 405B by Meta AI, context windows of 400K vs 128K, tested across 12 shared challenges. Updated April 2026.
Which is better, GPT-5.3-Codex or Llama 3.1 405B?
GPT-5.3-Codex and Llama 3.1 405B are both competitive models. GPT-5.3-Codex costs $1.75/M input tokens vs $2.7/M for Llama 3.1 405B. Context windows: 400K vs 128K tokens. Compare their real outputs side by side below.
Key Differences Between GPT-5.3-Codex and Llama 3.1 405B
GPT-5.3-Codex is made by openai while Llama 3.1 405B is from meta. GPT-5.3-Codex has a 400K token context window compared to Llama 3.1 405B's 128K. On pricing, GPT-5.3-Codex costs $1.75/M input tokens vs $2.7/M for Llama 3.1 405B.
No community votes yet. On paper, GPT-5.3-Codex has the edge — newer, bigger context window.
Llama 3.1 405B is 4.5x cheaper per token — worth considering if cost matters.
Style Comparison
GPT-5.3-Codex uses 654.6x more bold
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279 AI models invented the same fake scientist.
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