# Claude Opus 5.5 vs Llama 3.1 405B Instruct

As of Oct 15, 2026, Claude Opus 5.5 leads Llama 3.1 405B Instruct in 2 of 2 shared categories: General LLM and Science.

Claude Opus 5.5: $8.000000000000002 per 1M blended tokens.

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

Claude Opus 5.5: closed weights.

Llama 3.1 405B Instruct: open weights.

- Which to pick, General LLM: As of Oct 15, 2026, Claude Opus 5.5 leads Llama 3.1 405B Instruct in General LLM at #2 against #5.
- Which to pick, Science: As of Oct 15, 2026, Claude Opus 5.5 leads Llama 3.1 405B Instruct in Science at #31 against #124.

As of Oct 15, 2026, Claude Opus 5.5 is tied for state of the art in Reasoning (since Oct 2, 2026; 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).