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Atria Dawn Preview vs Claude Opus 5.5

Claude Opus 5.5 leads the LLM Stats Score 59.8 to 51.8.

Shanghai AI Laboratory · Anthropic · Updated for 2026

Which is better?

Claude Opus 5.5 leads the overall LLM Stats Score 59.8 to 51.8, ranking #1 overall.

The models split the 2 individual benchmarks reported for both models evenly.

Based on current LLM Stats indexes, shared benchmarks, pricing, and model metadata for 2026.

Choose Atria Dawn Preview

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

Choose Claude Opus 5.5

  • overall performance matters — it scores 59.8 and ranks #1 on LLM Stats
  • your work emphasizes reasoning and coding — it leads those capability indexes
  • you want the most recent training data — it shipped Sep 2026

At a glance

The differences that matter most.

Atria Dawn Preview
Shanghai AI Laboratory
Claude Opus 5.5
Anthropic
Core performance indexes
LLM Stats Score
51.8
#11
59.8
#1
Reasoning
50.1
#13
57.9
#1
Coding
35.3
#29
51.8
#1
Agents
38.1
#11
44.6
#2
Cost, coverage & limits
Benchmark wins
1 of 2
1 of 2
Input price
— / M
$4.00 / M
Output price
— / M
$20.00 / M
Context window
—
1,000,000

Capability indexes

Additional strengths measured across groups of related public benchmarks

1 shared
Index
Atria Dawn Preview
Claude Opus 5.5
Tool use
28.3#18
32.9#2
Conservative TrueSkill rating · higher is betterHow scores work

Individual benchmarks

12 reported for Atria Dawn Preview · 31 for Claude Opus 5.5

2 shared

Atria Dawn Preview outperforms in 1 benchmarks (AutomationBench), while Claude Opus 5.5 is better at 1 benchmark (SWE-Bench Pro).

Both models are evenly matched across the benchmarks.

Tue Sep 22 2026 • llm-stats.com

Human preference

Blind head-to-head votes and playground preference scores

Context Window

Maximum input and output token capacity

Only Claude Opus 5.5 specifies input context (1,000,000 tokens). Only Claude Opus 5.5 specifies output context (128,000 tokens).

Shanghai AI Laboratory
Atria Dawn Preview
Input- tokens
Output- tokens
Anthropic
Claude Opus 5.5
Input1,000,000 tokens
Output128,000 tokens
Tue Sep 22 2026 • llm-stats.com

Input capabilities

Documented input modalities across available providers

Claude Opus 5.5 supports multimodal inputs, whereas Atria Dawn Preview does not.

Claude Opus 5.5 can handle both text and other forms of data like images, making it suitable for multimodal applications.

Atria Dawn Preview

Text
Images
Audio
Video

Claude Opus 5.5

Text
Images
Audio
Video

License

Usage and distribution terms

Atria Dawn Preview is licensed under MIT, while Claude Opus 5.5 uses a proprietary license.

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

Atria Dawn Preview

MIT

Open weights

Claude Opus 5.5

Proprietary

Closed source

Release Timeline

When each model was launched

Atria Dawn Preview was released on 2026-09-11, while Claude Opus 5.5 was released on 2026-09-22.

Claude Opus 5.5 is 0 month newer than Atria Dawn Preview.

Atria Dawn Preview

Sep 11, 2026

1 weeks ago

Claude Opus 5.5

Sep 22, 2026

0 days ago

1w newer

Knowledge Cutoff

When training data ends

Claude Opus 5.5 has a documented knowledge cutoff of 2026-06-01, while Atria Dawn Preview's cutoff date is not specified.

We can confirm Claude Opus 5.5's training data extends to 2026-06-01, but cannot make a direct comparison without Atria Dawn Preview's cutoff date.

Atria Dawn Preview

—

Claude Opus 5.5

Jun 2026

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Judge for yourself.

Run your own prompts against Atria Dawn Preview and Claude Opus 5.5 side-by-side, then vote on the output you prefer.

Atria Dawn Preview
✓ Preferred
Claude Opus 5.5
Open in Playground

FAQ

Common questions about Atria Dawn Preview vs Claude Opus 5.5.

Which is better, Atria Dawn Preview or Claude Opus 5.5?

Claude Opus 5.5 leads the LLM Stats Score 59.8 to 51.8. Atria Dawn Preview is made by Shanghai AI Laboratory and Claude Opus 5.5 is made by Anthropic. The best choice depends on your use case — compare their capability indexes, individual benchmarks, pricing, and limits above.

How does Atria Dawn Preview compare to Claude Opus 5.5 in benchmarks?

Atria Dawn Preview scores DeepSearchQA: 96.0%, BrowseComp: 92.5%, CyberGym: 86.5%, MLE-Bench Lite: 86.2%, WideSearch: 81.9%. Claude Opus 5.5 scores BenchCAD (with Python tool): 96.2%, Global-MMLU: 94.3%, SWE-bench Multilingual: 93.9%, MILU: 93.1%, ArXivMath: 91.2%.

What are the context window sizes for Atria Dawn Preview and Claude Opus 5.5?

Atria Dawn Preview supports an unknown number of tokens and Claude Opus 5.5 supports 1.0M tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between Atria Dawn Preview and Claude Opus 5.5?

Key differences include LLM Stats Score (51.8 vs 59.8), multimodal support (no vs yes), licensing (MIT vs Proprietary). See the full comparison above for benchmark-by-benchmark results.

Who makes Atria Dawn Preview and Claude Opus 5.5?

Atria Dawn Preview is developed by Shanghai AI Laboratory and Claude Opus 5.5 is developed by Anthropic.

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