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Gemini Diffusion vs GPT-5.1 Codex Mini

Gemini Diffusion and GPT-5.1 Codex Mini are closely matched at 0.4 and -3.1 on the LLM Stats Score.

Google · OpenAI · Updated for 2026

Which is better?

Gemini Diffusion and GPT-5.1 Codex Mini are closely matched on the overall LLM Stats Score at 0.4 and -3.1.

In the 1 individual benchmarks reported for both models, GPT-5.1 Codex Mini wins 1; this is a narrower head-to-head signal than the composite indexes.

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

Choose Gemini Diffusion

  • you are already invested in the Google ecosystem

Choose GPT-5.1 Codex Mini

  • you value its reported benchmark strengths — it wins 1 of 1 exact shared results
  • 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
Core performance indexes
LLM Stats Score
0.4
#349
-3.1
#366
Reasoning
0.4
#341
-3.0
#358
Cost, coverage & limits
Benchmark wins
0 of 1
1 of 1
Input price
— / M
$0.25 / M
Output price
— / M
$2.00 / M
Context window
—
400,000

Individual benchmarks

10 reported for Gemini Diffusion · 1 for GPT-5.1 Codex Mini

1 shared

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.

Fri Oct 23 2026 • llm-stats.com

Human preference

Blind head-to-head votes and playground 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
Fri Oct 23 2026 • llm-stats.com

Input capabilities

Documented input modalities across available providers

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

1.4 years ago

GPT-5.1 Codex Mini

Nov 12, 2025

11 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?

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?

Gemini Diffusion and GPT-5.1 Codex Mini are closely matched on the LLM Stats Score at 0.4 and -3.1. 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 capability indexes, individual benchmarks, pricing, and limits 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 LLM Stats Score (0.4 vs -3.1), 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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