# Claude Opus 4.5 vs Llama 3.1 405B Instruct

As of Oct 15, 2026, Claude Opus 4.5 leads Llama 3.1 405B Instruct in 1 of 2 shared categories: Science.

Claude Opus 4.5: $10 per 1M blended tokens.

Llama 3.1 405B Instruct: price per 1M tokens is unset in the catalog.

Claude Opus 4.5: closed weights.

Llama 3.1 405B Instruct: open weights.

- Which to pick, General LLM: As of Oct 15, 2026, Llama 3.1 405B Instruct leads Claude Opus 4.5 in General LLM at #5 against #41.
- Which to pick, Science: As of Oct 15, 2026, Claude Opus 4.5 leads Llama 3.1 405B Instruct in Science at #68 against #124.

As of Oct 15, 2026, Claude Opus 4.5 is a former state-of-the-art holder in Reasoning (since Dec 1, 2025; sources LMArena Text (style-controlled, hard prompts); methodology v1.0).

As of Oct 15, 2026, Llama 3.1 405B Instruct is a former state-of-the-art holder in General LLM (since Aug 28, 2024; sources LMArena Text (style-controlled, overall); methodology v1.0).