Model Comparison

Claude Fable 5 vs Nemotron 3 Ultra (550B A55B)Which is better in 2026?

Claude Fable 5 significantly outperforms across most benchmarks.

Verdict: Claude Fable 5 vs Nemotron 3 Ultra (550B A55B) — which is better?

Claude Fable 5 (by Anthropic) and Nemotron 3 Ultra (550B A55B) (by NVIDIA) are two of the AI models people compare most. Here is how they stack up on benchmarks, price and capabilities, and which one to pick in 2026.

Claude Fable 5 outperforms in 5 benchmarks (Finance Agent v2, GDPval-AA, Humanity's Last Exam, SWE-Bench Verified, Terminal-Bench 2.1), while Nemotron 3 Ultra (550B A55B) is better at 0 benchmarks. Claude Fable 5 significantly outperforms across most benchmarks.

Choose Claude Fable 5 if…

  • you want the strongest raw capability — it leads on 5 of 5 shared benchmarks
  • you want the most recent training data — it shipped Jun 2026

Choose Nemotron 3 Ultra (550B A55B) if…

  • you need open weights you can self-host or fine-tune

Performance Benchmarks

Comparative analysis across standard metrics

5 benchmarks

Claude Fable 5 outperforms in 5 benchmarks (Finance Agent v2, GDPval-AA, Humanity's Last Exam, SWE-Bench Verified, Terminal-Bench 2.1), while Nemotron 3 Ultra (550B A55B) is better at 0 benchmarks.

Claude Fable 5 significantly outperforms across most benchmarks.

Fri Jul 17 2026 • llm-stats.com

Arena Performance

Human preference votes

Context Window

Maximum input and output token capacity

Only Claude Fable 5 specifies input context (1,000,000 tokens). Only Claude Fable 5 specifies output context (128,000 tokens).

Anthropic
Claude Fable 5
Input1,000,000 tokens
Output128,000 tokens
NVIDIA
Nemotron 3 Ultra (550B A55B)
Input- tokens
Output- tokens
Fri Jul 17 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Claude Fable 5 supports multimodal inputs, whereas Nemotron 3 Ultra (550B A55B) does not.

Claude Fable 5 can handle both text and other forms of data like images, making it suitable for multimodal applications.

Claude Fable 5

Text
Images
Audio
Video

Nemotron 3 Ultra (550B A55B)

Text
Images
Audio
Video

License

Usage and distribution terms

Claude Fable 5 is licensed under a proprietary license, while Nemotron 3 Ultra (550B A55B) uses OpenMDW License v1.1.

License differences may affect how you can use these models in commercial or open-source projects.

Claude Fable 5

Proprietary

Closed source

Nemotron 3 Ultra (550B A55B)

OpenMDW License v1.1

Open weights

Release Timeline

When each model was launched

Claude Fable 5 was released on 2026-06-09, while Nemotron 3 Ultra (550B A55B) was released on 2026-06-04.

Claude Fable 5 is 0 month newer than Nemotron 3 Ultra (550B A55B).

Claude Fable 5

Jun 9, 2026

1 months ago

5d newer
Nemotron 3 Ultra (550B A55B)

Jun 4, 2026

1 months ago

Knowledge Cutoff

When training data ends

Nemotron 3 Ultra (550B A55B) has a documented knowledge cutoff of 2025-09-30, while Claude Fable 5's cutoff date is not specified.

We can confirm Nemotron 3 Ultra (550B A55B)'s training data extends to 2025-09-30, but cannot make a direct comparison without Claude Fable 5's cutoff date.

Claude Fable 5

—

Nemotron 3 Ultra (550B A55B)

Sep 2025

Outputs Comparison

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Key Takeaways

Anthropic
Larger context window (1,000,000 tokens)
Supports multimodal inputs
Higher Finance Agent v2 score (56.3% vs 37.5%)
Higher GDPval-AA score (60.5% vs 39.4%)
Higher Humanity's Last Exam score (64.5% vs 37.4%)
Higher SWE-Bench Verified score (95.0% vs 70.7%)
Higher Terminal-Bench 2.1 score (84.3% vs 56.4%)
NVIDIA
Has open weights

Detailed Comparison

Interactive Arena

Judge for yourself.

Run your own prompts against Claude Fable 5 and Nemotron 3 Ultra (550B A55B) side-by-side, then vote on the output you prefer.

Claude Fable 5
✓ Preferred
Nemotron 3 Ultra (550B A55B)
Open in Playground
AI Model Comparison Table
Feature
Anthropic
Claude Fable 5
NVIDIA
Nemotron 3 Ultra (550B A55B)

FAQ

Common questions about Claude Fable 5 vs Nemotron 3 Ultra (550B A55B).

Which is better, Claude Fable 5 or Nemotron 3 Ultra (550B A55B)?

Claude Fable 5 significantly outperforms across most benchmarks. Claude Fable 5 is made by Anthropic and Nemotron 3 Ultra (550B A55B) is made by NVIDIA. The best choice depends on your use case — compare their benchmark scores, pricing, and capabilities above.

How does Claude Fable 5 compare to Nemotron 3 Ultra (550B A55B) in benchmarks?

Claude Fable 5 scores SWE-Bench Verified: 95.0%, FrontierSWE: 90.0%, OSWorld-Verified: 85.0%, Terminal-Bench 2.1: 84.3%, SWE-Bench Pro: 80.0%. Nemotron 3 Ultra (550B A55B) scores RULER: 94.7%, IMO-AnswerBench: 92.3%, PinchBench: 90.0%, LiveCodeBench v6: 89.0%, GPQA: 87.0%.

What are the context window sizes for Claude Fable 5 and Nemotron 3 Ultra (550B A55B)?

Claude Fable 5 supports 1.0M tokens and Nemotron 3 Ultra (550B A55B) supports an unknown number of tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between Claude Fable 5 and Nemotron 3 Ultra (550B A55B)?

Key differences include multimodal support (yes vs no), licensing (Proprietary vs OpenMDW License v1.1). See the full comparison above for benchmark-by-benchmark results.

Who makes Claude Fable 5 and Nemotron 3 Ultra (550B A55B)?

Claude Fable 5 is developed by Anthropic and Nemotron 3 Ultra (550B A55B) is developed by NVIDIA.

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