Model Comparison

Grok 4 Fast vs Nova 2 OmniWhich is better in 2026?

Nova 2 Omni significantly outperforms across most benchmarks.

Verdict: Grok 4 Fast vs Nova 2 Omni — which is better?

Grok 4 Fast (by xAI) and Nova 2 Omni (by Amazon) 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.

Grok 4 Fast outperforms in 0 benchmarks, while Nova 2 Omni is better at 1 benchmark (AIME 2025). Nova 2 Omni significantly outperforms across most benchmarks.

Choose Grok 4 Fast if…

  • you want predictable pricing at $0.20/M input and $0.50/M output

Choose Nova 2 Omni if…

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

Performance Benchmarks

Comparative analysis across standard metrics

1 benchmarks

Grok 4 Fast outperforms in 0 benchmarks, while Nova 2 Omni is better at 1 benchmark (AIME 2025).

Nova 2 Omni significantly outperforms across most benchmarks.

Tue Jul 21 2026 • llm-stats.com

Arena Performance

Human preference votes

Context Window

Maximum input and output token capacity

Only Grok 4 Fast specifies input context (2,000,000 tokens). Only Grok 4 Fast specifies output context (30,000 tokens).

xAI
Grok 4 Fast
Input2,000,000 tokens
Output30,000 tokens
Amazon
Nova 2 Omni
Input- tokens
Output- tokens
Tue Jul 21 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Both Grok 4 Fast and Nova 2 Omni support multimodal inputs.

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

Grok 4 Fast

Text
Images
Audio
Video

Nova 2 Omni

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.

Grok 4 Fast

Proprietary

Closed source

Nova 2 Omni

Proprietary

Closed source

Release Timeline

When each model was launched

Grok 4 Fast was released on 2025-08-28, while Nova 2 Omni was released on 2025-12-02.

Nova 2 Omni is 3 months newer than Grok 4 Fast.

Grok 4 Fast

Aug 28, 2025

10 months ago

Nova 2 Omni

Dec 2, 2025

7 months ago

3mo 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→

Key Takeaways

xAI
Larger context window (2,000,000 tokens)
Amazon
Higher AIME 2025 score (92.1% vs 92.0%)

Detailed Comparison

Interactive Arena

Judge for yourself.

Run your own prompts against Grok 4 Fast and Nova 2 Omni side-by-side, then vote on the output you prefer.

Grok 4 Fast
✓ Preferred
Nova 2 Omni
Open in Playground
AI Model Comparison Table
Feature
xAI
Grok 4 Fast
Amazon
Nova 2 Omni

FAQ

Common questions about Grok 4 Fast vs Nova 2 Omni.

Which is better, Grok 4 Fast or Nova 2 Omni?

Nova 2 Omni significantly outperforms across most benchmarks. Grok 4 Fast is made by xAI and Nova 2 Omni is made by Amazon. The best choice depends on your use case — compare their benchmark scores, pricing, and capabilities above.

How does Grok 4 Fast compare to Nova 2 Omni in benchmarks?

Grok 4 Fast scores SimpleQA: 95.0%, HMMT 2025: 93.3%, AIME 2025: 92.0%, GPQA: 85.7%, LiveCodeBench: 80.0%. Nova 2 Omni scores AIME 2025: 92.1%, RefCOCOg: 86.3%, ScreenSpot: 85.4%, MMLU-Pro: 80.7%, Tau2 Telecom: 80.0%.

What are the context window sizes for Grok 4 Fast and Nova 2 Omni?

Grok 4 Fast supports 2.0M tokens and Nova 2 Omni supports an unknown number of tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

Who makes Grok 4 Fast and Nova 2 Omni?

Grok 4 Fast is developed by xAI and Nova 2 Omni is developed by Amazon.

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