GPT-5.1 Chat vs Llama 3.1 405B
Compare GPT-5.1 Chat by OpenAI against Llama 3.1 405B by Meta AI, context windows of 128K vs 128K, tested across 12 shared challenges. Updated April 2026.
Which is better, GPT-5.1 Chat or Llama 3.1 405B?
GPT-5.1 Chat and Llama 3.1 405B are both competitive models. GPT-5.1 Chat costs $1.25/M input tokens vs $2.7/M for Llama 3.1 405B. Context windows: 128K vs 128K tokens. Compare their real outputs side by side below.
Key Differences Between GPT-5.1 Chat and Llama 3.1 405B
GPT-5.1 Chat is made by openai while Llama 3.1 405B is from meta. GPT-5.1 Chat has a 128K token context window compared to Llama 3.1 405B's 128K. On pricing, GPT-5.1 Chat costs $1.25/M input tokens vs $2.7/M for 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 3.2x cheaper per token — worth considering if cost matters.
Style Comparison
GPT-5.1 Chat uses 108.9x more bold
vsAsk them anything yourself
Some models write identically. You are paying for the brand.
178 models fingerprinted across 32 writing dimensions. Free research.
185x
price gap between models that write identically
178
models
12
clone pairs
32
dimensions
279 AI models invented the same fake scientist.
We read every word. 250 models. 2.14 million words. This is what we found.
