Llama 3.1 405B is Meta's 405-billion-parameter dense open-weight model, released in July 2024. It was the first openly available model to reach frontier-level performance on reasoning, coding, and multilingual tasks, with a 128K-token context window and native tool-use support.
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WHY WE PICKED IT
Llama 3.1 405B remains a landmark open release: it proved open weights could compete with proprietary frontier models and still serves as a high-quality baseline for research and synthetic-data generation.
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The benchmark gap has largely closed: open models now score within a point of the closed frontier on...
Capacity decides whether a model runs. Bandwidth decides how fast it talks, and it is the number mos...
Running a frontier open model locally is a memory problem before it is a speed problem, and a bandwi...
Abliteration removes a model's ability to refuse by deleting one direction from its activations. It ...
Comprehensive comparison of the best large language models in 2026 including ChatGPT, Claude, Gemini...
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FREQUENTLY ASKED QUESTIONS
Is Llama 3.1 405B free?
Yes, Llama 3.1 405B is completely free to use.
Does Llama 3.1 405B have an API?
Yes, Llama 3.1 405B offers an API for programmatic integration.
What is Llama 3.1 405B best for?
Llama 3.1 405B is best for Frontier Open Research. Llama 3. Llama 3.1 405B remains a landmark open release: it proved open weights could compete with proprietary frontier models and still serves as a high-quality baseline for research and synthetic-data generation.
What platforms does Llama 3.1 405B support?
Llama 3.1 405B supports web, api, local.
Is Llama 3.1 405B open source?
Yes, Llama 3.1 405B is open source. You can access the source code on GitHub at https://github.com/meta-llama/llama-models.
How do I use Llama 3.1 405B?
Llama 3.1 405B is a large language model for text generation, analysis, and conversation. Access through the web interface. Enter prompts or questions to get responses.
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