Llama 3.1 405B vs GPT-5

Compare Llama 3.1 405B by Meta AI against GPT-5 by OpenAI, context windows of 128K vs 400K, tested across 7 shared challenges. Updated April 2026.

Which is better, Llama 3.1 405B or GPT-5?

Llama 3.1 405B and GPT-5 are both competitive models. Llama 3.1 405B costs $2.7/M input tokens vs $1.25/M for GPT-5. Context windows: 128K vs 400K tokens. Compare their real outputs side by side below.

Key Differences Between Llama 3.1 405B and GPT-5

Llama 3.1 405B is made by meta while GPT-5 is from openai. Llama 3.1 405B has a 128K token context window compared to GPT-5's 400K. On pricing, Llama 3.1 405B costs $2.7/M input tokens vs $1.25/M for GPT-5.

Our Verdict
GPT-5
GPT-5
Llama 3.1 405B
Llama 3.1 405BRunner-up

No community votes yet. On paper, GPT-5 has the edge — newer, bigger context window.

Llama 3.1 405B is 3.2x cheaper per token — worth considering if cost matters.

Too close to call
Writing DNA

Style Comparison

Similarity
72%

GPT-5 uses 18.9x more bold

Llama 3.1 405B
GPT-5
56%Vocabulary65%
15wSentence Length13w
0.41Hedging0.20
0.0Bold0.2
1.9Lists4.6
0.03Emoji0.00
0.00Headings0.16
0.16Transitions0.03
Based on 5 + 16 text responses
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Llama 3.1 405BGPT-5

279 AI models invented the same fake scientist.

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