Nous: Hermes 4 405B

● Excellent

by Nousresearch Open Weight Reasoning Rank #43 of 80

8.4
/ 10

Hermes 4 is a large-scale reasoning model built on Meta-Llama-3.1-405B and released by Nous Research. It introduces a hybrid reasoning mode, where the model can choose to deliberate internally with...

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Specifications

Specifications for Nous: Hermes 4 405B
AttributeValue
Lab Nousresearch
Tags Open Weight Reasoning
Overall Score 8.4/10
Release Date 2025-08
Context Window 131,072 tokens
Input Price / 1M $1.00
Output Price / 1M $3.00
Input Modalities Text
Output Modalities Text

Strengths

  • Hybrid reasoning mode auto-decides when to think deeply
  • Strong instruction following and tool use
  • Open-weight on Llama 3.1 405B base
  • Uncensored — no refusal for controversial topics

Weaknesses

  • Based on older Llama 3.1 architecture
  • Very large model — slow and expensive to run
  • Less competitive on raw benchmarks vs latest models

Best For

  • Complex multi-step reasoning
  • Creative and uncensored writing
  • Research and experimentation
  • Tool-use and agentic workflows

Sources & Further Reading

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Scores are aggregated from public benchmarks (MMLU, HumanEval, MATH, GSM8K, LMSYS) and normalized to a 1–10 scale. Methodology →