Model Comparison

Kimi K3 vs Nemotron 3 Ultra (550B A55B)Which is better in 2026?

Kimi K3 significantly outperforms across most benchmarks.

Verdict: Kimi K3 vs Nemotron 3 Ultra (550B A55B) — which is better?

Kimi K3 (by Moonshot AI) 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.

Kimi K3 outperforms in 5 benchmarks (BrowseComp, GDPval-AA, GPQA, Humanity's Last Exam, Terminal-Bench 2.1), while Nemotron 3 Ultra (550B A55B) is better at 0 benchmarks. Kimi K3 significantly outperforms across most benchmarks.

Choose Kimi K3 if…

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

Kimi K3 outperforms in 5 benchmarks (BrowseComp, GDPval-AA, GPQA, Humanity's Last Exam, Terminal-Bench 2.1), while Nemotron 3 Ultra (550B A55B) is better at 0 benchmarks.

Kimi K3 significantly outperforms across most benchmarks.

Fri Jul 17 2026 • llm-stats.com

Arena Performance

Human preference votes

Model Size

Parameter count comparison

2250.0B diff

Kimi K3 has 2250.0B more parameters than Nemotron 3 Ultra (550B A55B), making it 409.1% larger.

Moonshot AI
Kimi K3
2.8Tparameters
NVIDIA
Nemotron 3 Ultra (550B A55B)
550.0Bparameters
2800.0B
Kimi K3
550.0B
Nemotron 3 Ultra (550B A55B)

Context Window

Maximum input and output token capacity

Only Kimi K3 specifies input context (1,048,576 tokens). Only Kimi K3 specifies output context (1,048,576 tokens).

Moonshot AI
Kimi K3
Input1,048,576 tokens
Output1,048,576 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

Kimi K3 supports multimodal inputs, whereas Nemotron 3 Ultra (550B A55B) does not.

Kimi K3 can handle both text and other forms of data like images, making it suitable for multimodal applications.

Kimi K3

Text
Images
Audio
Video

Nemotron 3 Ultra (550B A55B)

Text
Images
Audio
Video

Release Timeline

When each model was launched

Kimi K3 was released on 2026-07-16, while Nemotron 3 Ultra (550B A55B) was released on 2026-06-04.

Kimi K3 is 1 month newer than Nemotron 3 Ultra (550B A55B).

Kimi K3

Jul 16, 2026

1 days ago

1mo 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 Kimi K3'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 Kimi K3's cutoff date.

Kimi K3

—

Nemotron 3 Ultra (550B A55B)

Sep 2025

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Key Takeaways

Moonshot AI
Larger context window (1,048,576 tokens)
Supports multimodal inputs
Higher BrowseComp score (91.2% vs 44.4%)
Higher GDPval-AA score (55.6% vs 39.4%)
Higher GPQA score (93.5% vs 87.0%)
Higher Humanity's Last Exam score (56.0% vs 37.4%)
Higher Terminal-Bench 2.1 score (88.3% vs 56.4%)
NVIDIA

No standout differentiators in the data we have for this pair.

Detailed Comparison

Interactive Arena

Judge for yourself.

Run your own prompts against Kimi K3 and Nemotron 3 Ultra (550B A55B) side-by-side, then vote on the output you prefer.

Kimi K3
✓ Preferred
Nemotron 3 Ultra (550B A55B)
Open in Playground
AI Model Comparison Table
Feature
Moonshot AI
Kimi K3
NVIDIA
Nemotron 3 Ultra (550B A55B)

FAQ

Common questions about Kimi K3 vs Nemotron 3 Ultra (550B A55B).

Which is better, Kimi K3 or Nemotron 3 Ultra (550B A55B)?

Kimi K3 significantly outperforms across most benchmarks. Kimi K3 is made by Moonshot AI 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 Kimi K3 compare to Nemotron 3 Ultra (550B A55B) in benchmarks?

Kimi K3 scores MathVision: 97.8%, DeepSearchQA: 95.0%, GPQA: 93.5%, CharXiv-R: 91.3%, BrowseComp: 91.2%. 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 Kimi K3 and Nemotron 3 Ultra (550B A55B)?

Kimi K3 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 Kimi K3 and Nemotron 3 Ultra (550B A55B)?

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

Who makes Kimi K3 and Nemotron 3 Ultra (550B A55B)?

Kimi K3 is developed by Moonshot AI and Nemotron 3 Ultra (550B A55B) is developed by NVIDIA.

Related comparisons