Model Comparison

LongCat-Flash-Thinking-2601 vs Nemotron 3 Ultra (550B A55B)Which is better in 2026?

Nemotron 3 Ultra (550B A55B) significantly outperforms across most benchmarks.

Verdict: LongCat-Flash-Thinking-2601 vs Nemotron 3 Ultra (550B A55B) — which is better?

LongCat-Flash-Thinking-2601 (by Meituan) 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.

LongCat-Flash-Thinking-2601 outperforms in 1 benchmarks (BrowseComp), while Nemotron 3 Ultra (550B A55B) is better at 4 benchmarks (GPQA, Humanity's Last Exam, IMO-AnswerBench, SWE-Bench Verified). Nemotron 3 Ultra (550B A55B) significantly outperforms across most benchmarks.

Choose LongCat-Flash-Thinking-2601 if…

  • you want predictable pricing at $0.30/M input and $1.20/M output

Choose Nemotron 3 Ultra (550B A55B) if…

  • you want the strongest raw capability — it leads on 4 of 5 shared benchmarks
  • you want the most recent training data — it shipped Jun 2026

Performance Benchmarks

Comparative analysis across standard metrics

5 benchmarks

LongCat-Flash-Thinking-2601 outperforms in 1 benchmarks (BrowseComp), while Nemotron 3 Ultra (550B A55B) is better at 4 benchmarks (GPQA, Humanity's Last Exam, IMO-AnswerBench, SWE-Bench Verified).

Nemotron 3 Ultra (550B A55B) significantly outperforms across most benchmarks.

Mon Jul 27 2026 • llm-stats.com

Arena Performance

Human preference votes

Model Size

Parameter count comparison

10.0B diff

LongCat-Flash-Thinking-2601 has 10.0B more parameters than Nemotron 3 Ultra (550B A55B), making it 1.8% larger.

Meituan
LongCat-Flash-Thinking-2601
560.0Bparameters
NVIDIA
Nemotron 3 Ultra (550B A55B)
550.0Bparameters
560.0B
LongCat-Flash-Thinking-2601
550.0B
Nemotron 3 Ultra (550B A55B)

Context Window

Maximum input and output token capacity

Only LongCat-Flash-Thinking-2601 specifies input context (128,000 tokens). Only LongCat-Flash-Thinking-2601 specifies output context (128,000 tokens).

Meituan
LongCat-Flash-Thinking-2601
Input128,000 tokens
Output128,000 tokens
NVIDIA
Nemotron 3 Ultra (550B A55B)
Input- tokens
Output- tokens
Mon Jul 27 2026 • llm-stats.com

License

Usage and distribution terms

LongCat-Flash-Thinking-2601 is licensed under MIT, 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.

LongCat-Flash-Thinking-2601

MIT

Open weights

Nemotron 3 Ultra (550B A55B)

OpenMDW License v1.1

Open weights

Release Timeline

When each model was launched

LongCat-Flash-Thinking-2601 was released on 2026-01-14, while Nemotron 3 Ultra (550B A55B) was released on 2026-06-04.

Nemotron 3 Ultra (550B A55B) is 5 months newer than LongCat-Flash-Thinking-2601.

LongCat-Flash-Thinking-2601

Jan 14, 2026

6 months ago

Nemotron 3 Ultra (550B A55B)

Jun 4, 2026

1 months ago

4mo newer

Knowledge Cutoff

When training data ends

Nemotron 3 Ultra (550B A55B) has a documented knowledge cutoff of 2025-09-30, while LongCat-Flash-Thinking-2601'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 LongCat-Flash-Thinking-2601's cutoff date.

LongCat-Flash-Thinking-2601

—

Nemotron 3 Ultra (550B A55B)

Sep 2025

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Key Takeaways

Meituan
Larger context window (128,000 tokens)
Higher BrowseComp score (56.6% vs 44.4%)
NVIDIA
Higher GPQA score (87.0% vs 80.5%)
Higher Humanity's Last Exam score (37.4% vs 25.2%)
Higher IMO-AnswerBench score (92.3% vs 78.6%)
Higher SWE-Bench Verified score (70.7% vs 70.0%)

Detailed Comparison

Interactive Arena

Judge for yourself.

Run your own prompts against LongCat-Flash-Thinking-2601 and Nemotron 3 Ultra (550B A55B) side-by-side, then vote on the output you prefer.

LongCat-Flash-Thinking-2601
✓ Preferred
Nemotron 3 Ultra (550B A55B)
Open in Playground
AI Model Comparison Table
Feature
Meituan
LongCat-Flash-Thinking-2601
NVIDIA
Nemotron 3 Ultra (550B A55B)

FAQ

Common questions about LongCat-Flash-Thinking-2601 vs Nemotron 3 Ultra (550B A55B).

Which is better, LongCat-Flash-Thinking-2601 or Nemotron 3 Ultra (550B A55B)?

Nemotron 3 Ultra (550B A55B) significantly outperforms across most benchmarks. LongCat-Flash-Thinking-2601 is made by Meituan 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 LongCat-Flash-Thinking-2601 compare to Nemotron 3 Ultra (550B A55B) in benchmarks?

LongCat-Flash-Thinking-2601 scores AIME 2025: 99.6%, Tau2 Telecom: 99.3%, Tau2 Retail: 88.6%, LiveCodeBench: 82.8%, GPQA: 80.5%. 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 LongCat-Flash-Thinking-2601 and Nemotron 3 Ultra (550B A55B)?

LongCat-Flash-Thinking-2601 supports 128K 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 LongCat-Flash-Thinking-2601 and Nemotron 3 Ultra (550B A55B)?

Key differences include licensing (MIT vs OpenMDW License v1.1). See the full comparison above for benchmark-by-benchmark results.

Who makes LongCat-Flash-Thinking-2601 and Nemotron 3 Ultra (550B A55B)?

LongCat-Flash-Thinking-2601 is developed by Meituan and Nemotron 3 Ultra (550B A55B) is developed by NVIDIA.

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