Model Comparison

DiffusionGemma 26B-A4B vs GPT-5.5 ProWhich is better in 2026?

GPT-5.5 Pro significantly outperforms across most benchmarks.

Verdict: DiffusionGemma 26B-A4B vs GPT-5.5 Pro — which is better?

DiffusionGemma 26B-A4B (by Google) and GPT-5.5 Pro (by OpenAI) 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.

DiffusionGemma 26B-A4B outperforms in 0 benchmarks, while GPT-5.5 Pro is better at 1 benchmark (Humanity's Last Exam). GPT-5.5 Pro significantly outperforms across most benchmarks.

Choose DiffusionGemma 26B-A4B if…

  • you want the most recent training data — it shipped Jun 2026
  • you need open weights you can self-host or fine-tune

Choose GPT-5.5 Pro if…

  • you want the strongest raw capability — it leads on 1 of 1 shared benchmarks

Performance Benchmarks

Comparative analysis across standard metrics

1 benchmarks

DiffusionGemma 26B-A4B outperforms in 0 benchmarks, while GPT-5.5 Pro is better at 1 benchmark (Humanity's Last Exam).

GPT-5.5 Pro 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 GPT-5.5 Pro specifies input context (1,050,000 tokens). Only GPT-5.5 Pro specifies output context (128,000 tokens).

Google
DiffusionGemma 26B-A4B
Input- tokens
Output- tokens
OpenAI
GPT-5.5 Pro
Input1,050,000 tokens
Output128,000 tokens
Fri Jul 17 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Both DiffusionGemma 26B-A4B and GPT-5.5 Pro support multimodal inputs.

They are both capable of processing various types of data, offering versatility in application.

DiffusionGemma 26B-A4B

Text
Images
Audio
Video

GPT-5.5 Pro

Text
Images
Audio
Video

License

Usage and distribution terms

DiffusionGemma 26B-A4B is licensed under Apache 2.0, while GPT-5.5 Pro uses a proprietary license.

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

DiffusionGemma 26B-A4B

Apache 2.0

Open weights

GPT-5.5 Pro

Proprietary

Closed source

Release Timeline

When each model was launched

DiffusionGemma 26B-A4B was released on 2026-06-10, while GPT-5.5 Pro was released on 2026-04-23.

DiffusionGemma 26B-A4B is 2 months newer than GPT-5.5 Pro.

DiffusionGemma 26B-A4B

Jun 10, 2026

1 months ago

1mo newer
GPT-5.5 Pro

Apr 23, 2026

2 months ago

Knowledge Cutoff

When training data ends

DiffusionGemma 26B-A4B has a knowledge cutoff of 2025-01-01, while GPT-5.5 Pro has a cutoff of 2025-12-01.

GPT-5.5 Pro has more recent training data (up to 2025-12-01), making it potentially better informed about events through that date compared to DiffusionGemma 26B-A4B (2025-01-01).

DiffusionGemma 26B-A4B

Jan 2025

GPT-5.5 Pro

Dec 2025

11 mo newer

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Key Takeaways

Google
Has open weights
OpenAI
Larger context window (1,050,000 tokens)
Higher Humanity's Last Exam score (57.2% vs 11.9%)

Detailed Comparison

Interactive Arena

Judge for yourself.

Run your own prompts against DiffusionGemma 26B-A4B and GPT-5.5 Pro side-by-side, then vote on the output you prefer.

DiffusionGemma 26B-A4B
✓ Preferred
GPT-5.5 Pro
Open in Playground
AI Model Comparison Table
Feature
Google
DiffusionGemma 26B-A4B
OpenAI
GPT-5.5 Pro

FAQ

Common questions about DiffusionGemma 26B-A4B vs GPT-5.5 Pro.

Which is better, DiffusionGemma 26B-A4B or GPT-5.5 Pro?

GPT-5.5 Pro significantly outperforms across most benchmarks. DiffusionGemma 26B-A4B is made by Google and GPT-5.5 Pro is made by OpenAI. The best choice depends on your use case — compare their benchmark scores, pricing, and capabilities above.

How does DiffusionGemma 26B-A4B compare to GPT-5.5 Pro in benchmarks?

DiffusionGemma 26B-A4B scores MMMLU: 81.5%, MMLU-Pro: 77.6%, GPQA: 73.2%, MathVision: 70.5%, AIME 2026: 69.1%. GPT-5.5 Pro scores BrowseComp: 90.1%, GDPval-MM: 82.3%, Humanity's Last Exam: 57.2%, FrontierMath: 39.6%, GeneBench: 33.2%.

What are the context window sizes for DiffusionGemma 26B-A4B and GPT-5.5 Pro?

DiffusionGemma 26B-A4B supports an unknown number of tokens and GPT-5.5 Pro supports 1.1M tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between DiffusionGemma 26B-A4B and GPT-5.5 Pro?

Key differences include licensing (Apache 2.0 vs Proprietary). See the full comparison above for benchmark-by-benchmark results.

Who makes DiffusionGemma 26B-A4B and GPT-5.5 Pro?

DiffusionGemma 26B-A4B is developed by Google and GPT-5.5 Pro is developed by OpenAI.

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