Llama 3.1 405B: the first frontier-class open-weights model
Meta released Llama 3.1 including a 405B-parameter model with 128K context, which Meta said was competitive with GPT-4o and Claude 3.5 Sonnet — the first openly downloadable model at the frontier.
Key facts
- Released 23 July 2024
- Sizes: 8B, 70B, 405B; 128K context
- 405B trained on over 15T tokens using more than 16,000 H100 GPUs
- Mark Zuckerberg published 'Open Source AI Is the Path Forward' alongside
What happened
Meta released open weights for a dense 405B model along with a detailed technical report.
Why it matters
Narrowed the open–closed gap to months; open frontier weights reshaped policy debates and enabled wide distillation.
Changelog
- 2026-09-29: created
Related events
- Meta releases Llama 3 (8B, 70B) ★★★
- Meta releases Llama 4 Scout and Maverick ★★★
- Meta releases Llama 2 with a commercial-use license ★★★★
Sources (2)
id: 2024-07-23-llama-3-1-405b · updated 2026-09-29 · open in the interactive timeline