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Claude Mythos 5.1 vs Hy4 preview

Claude Mythos 5.1 and Hy4 preview are closely matched at 45.1 and 51.0 on the LLM Stats Score.

Anthropic · Tencent · Updated for 2026

Which is better?

Claude Mythos 5.1 and Hy4 preview are closely matched on the overall LLM Stats Score at 45.1 and 51.0.

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

Choose Claude Mythos 5.1

  • you want the most recent training data — it shipped Sep 2026

Choose Hy4 preview

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

At a glance

The differences that matter most.

Claude Mythos 5.1
Anthropic
Hy4 preview
Tencent
Core performance indexes
LLM Stats Score
45.1
#31
51.0
#13
Reasoning
44.4
#34
50.8
#10
Coding
37.5
#17
40.0
#12
Agents
34.5
#21
36.8
#14
Cost, coverage & limits
Benchmark wins
—
—
Input price
$10.00 / M
— / M
Output price
$50.00 / M
— / M
Context window
1,000,000
—

Individual benchmarks

1 reported for Claude Mythos 5.1 · 32 for Hy4 preview

No common benchmarks found

Claude Mythos 5.1 and Hy4 previewdon't have any common benchmark datasets to compare. They may have been evaluated on different testing suites.

Human preference

Blind head-to-head votes and playground preference scores

Context Window

Maximum input and output token capacity

Only Claude Mythos 5.1 specifies input context (1,000,000 tokens). Only Claude Mythos 5.1 specifies output context (128,000 tokens).

Anthropic
Claude Mythos 5.1
Input1,000,000 tokens
Output128,000 tokens
Tencent
Hy4 preview
Input- tokens
Output- tokens
Tue Sep 08 2026 • llm-stats.com

Input capabilities

Documented input modalities across available providers

Claude Mythos 5.1 supports multimodal inputs, whereas Hy4 preview does not.

Claude Mythos 5.1 can handle both text and other forms of data like images, making it suitable for multimodal applications.

Claude Mythos 5.1

Text
Images
Audio
Video

Hy4 preview

Text
Images
Audio
Video

License

Usage and distribution terms

Claude Mythos 5.1 is licensed under a proprietary license, while Hy4 preview uses Apache 2.0.

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

Claude Mythos 5.1

Proprietary

Closed source

Hy4 preview

Apache 2.0

Open weights

Release Timeline

When each model was launched

Claude Mythos 5.1 was released on 2026-09-01, while Hy4 preview was released on 2026-08-28.

Claude Mythos 5.1 is 0 month newer than Hy4 preview.

Claude Mythos 5.1

Sep 1, 2026

1 weeks ago

4d newer
Hy4 preview

Aug 28, 2026

1 weeks ago

Knowledge Cutoff

When training data ends

Neither model specifies a knowledge cutoff date.

Unable to compare the recency of their training data.

No cutoff dates available

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Judge for yourself.

Run your own prompts against Claude Mythos 5.1 and Hy4 preview side-by-side, then vote on the output you prefer.

Claude Mythos 5.1
✓ Preferred
Hy4 preview
Open in Playground

FAQ

Common questions about Claude Mythos 5.1 vs Hy4 preview.

Which is better, Claude Mythos 5.1 or Hy4 preview?

Claude Mythos 5.1 and Hy4 preview are closely matched on the LLM Stats Score at 45.1 and 51.0. Claude Mythos 5.1 is made by Anthropic and Hy4 preview is made by Tencent. The best choice depends on your use case — compare their capability indexes, individual benchmarks, pricing, and limits above.

How does Claude Mythos 5.1 compare to Hy4 preview in benchmarks?

Claude Mythos 5.1 scores Terminal-Bench 4.0: 60.9%. Hy4 preview scores GPQA: 92.3%, Terminal-Bench 2.1: 85.4%, WideSearch: 83.9%, MCP Atlas: 83.7%, SWE-bench Multilingual: 82.9%.

What are the context window sizes for Claude Mythos 5.1 and Hy4 preview?

Claude Mythos 5.1 supports 1.0M tokens and Hy4 preview 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 Mythos 5.1 and Hy4 preview?

Key differences include LLM Stats Score (45.1 vs 51.0), multimodal support (yes vs no), licensing (Proprietary vs Apache 2.0). See the full comparison above for benchmark-by-benchmark results.

Who makes Claude Mythos 5.1 and Hy4 preview?

Claude Mythos 5.1 is developed by Anthropic and Hy4 preview is developed by Tencent.

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