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Gemini Diffusion vs GPT-5.1 Codex Mini

GPT-5.1 Codex Mini significantly outperforms across most benchmarks.

Google · OpenAI · Updated for 2026

Which is better?

Gemini Diffusion outperforms in 0 benchmarks, while GPT-5.1 Codex Mini is better at 1 benchmark (AIME 2025). GPT-5.1 Codex Mini significantly outperforms across most benchmarks.

Based on current benchmark, pricing, and model metadata for 2026.

Choose Gemini Diffusion

  • you are already invested in the Google ecosystem

Choose GPT-5.1 Codex Mini

  • you want the strongest raw capability — it leads on 1 of 1 shared benchmarks
  • you want the most recent training data — it shipped Nov 2025

At a glance

The differences that matter most.

Gemini Diffusion
Google
GPT-5.1 Codex Mini
OpenAI
Benchmark wins
0 of 1
1 of 1
Input price
— / M
$0.25 / M
Output price
— / M
$2.00 / M
Context window
—
400,000
Released
May 2025
Nov 2025
License
Proprietary
Proprietary

Performance Benchmarks

Comparative analysis across standard metrics

1 benchmarks

Gemini Diffusion outperforms in 0 benchmarks, while GPT-5.1 Codex Mini is better at 1 benchmark (AIME 2025).

GPT-5.1 Codex Mini significantly outperforms across most benchmarks.

Wed Aug 26 2026 • llm-stats.com

Arena Performance

Playground indexes and blind preference scores

Context Window

Maximum input and output token capacity

Only GPT-5.1 Codex Mini specifies input context (400,000 tokens). Only GPT-5.1 Codex Mini specifies output context (128,000 tokens).

Google
Gemini Diffusion
Input- tokens
Output- tokens
OpenAI
GPT-5.1 Codex Mini
Input400,000 tokens
Output128,000 tokens
Wed Aug 26 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

GPT-5.1 Codex Mini supports multimodal inputs, whereas Gemini Diffusion does not.

GPT-5.1 Codex Mini can handle both text and other forms of data like images, making it suitable for multimodal applications.

Gemini Diffusion

Text
Images
Audio
Video

GPT-5.1 Codex Mini

Text
Images
Audio
Video

License

Usage and distribution terms

Both models are licensed under proprietary licenses.

Both models have usage restrictions defined by their respective organizations.

Gemini Diffusion

Proprietary

Closed source

GPT-5.1 Codex Mini

Proprietary

Closed source

Release Timeline

When each model was launched

Gemini Diffusion was released on 2025-05-20, while GPT-5.1 Codex Mini was released on 2025-11-12.

GPT-5.1 Codex Mini is 6 months newer than Gemini Diffusion.

Gemini Diffusion

May 20, 2025

1.3 years ago

GPT-5.1 Codex Mini

Nov 12, 2025

9 months ago

5mo newer

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 Gemini Diffusion and GPT-5.1 Codex Mini side-by-side, then vote on the output you prefer.

Gemini Diffusion
✓ Preferred
GPT-5.1 Codex Mini
Open in Playground

FAQ

Common questions about Gemini Diffusion vs GPT-5.1 Codex Mini.

Which is better, Gemini Diffusion or GPT-5.1 Codex Mini?

GPT-5.1 Codex Mini significantly outperforms across most benchmarks. Gemini Diffusion is made by Google and GPT-5.1 Codex Mini is made by OpenAI. The best choice depends on your use case — compare their benchmark scores, pricing, and capabilities above.

How does Gemini Diffusion compare to GPT-5.1 Codex Mini in benchmarks?

Gemini Diffusion scores HumanEval: 89.6%, MBPP: 76.0%, Global-MMLU-Lite: 69.1%, LBPP (v2): 56.8%, BigCodeBench: 45.4%. GPT-5.1 Codex Mini scores AIME 2025: 42.1%.

What are the context window sizes for Gemini Diffusion and GPT-5.1 Codex Mini?

Gemini Diffusion supports an unknown number of tokens and GPT-5.1 Codex Mini supports 400K tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between Gemini Diffusion and GPT-5.1 Codex Mini?

Key differences include multimodal support (no vs yes). See the full comparison above for benchmark-by-benchmark results.

Who makes Gemini Diffusion and GPT-5.1 Codex Mini?

Gemini Diffusion is developed by Google and GPT-5.1 Codex Mini is developed by OpenAI.

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