Grok 4.1 Fast vs o3 Mini

Compare Grok 4.1 Fast by xAI against o3 Mini by OpenAI, tested across 54 shared challenges. Updated April 2026.

Which is better, Grok 4.1 Fast or o3 Mini?

Grok 4.1 Fast and o3 Mini are both competitive models. Compare their real outputs side by side below.

Key Differences Between Grok 4.1 Fast and o3 Mini

Grok 4.1 Fast is made by xai while o3 Mini is from openai.

Our Verdict
Grok 4.1 Fast
Grok 4.1 Fast
o3 Mini
o3 MiniRunner-up

No community votes yet. On paper, Grok 4.1 Fast has the edge — bigger model tier, newer.

Too close to call
Writing DNA

Style Comparison

Similarity
96%

o3 Mini uses 4.3x more hedging

Grok 4.1 Fast
o3 Mini
67%Vocabulary65%
15wSentence Length17w
0.17Hedging0.74
4.7Bold3.9
3.7Lists1.7
0.00Emoji0.00
0.99Headings0.47
0.14Transitions0.38
Based on 24 + 12 text responses
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Ask them anything yourself

Grok 4.1 Fasto3 Mini

279 AI models invented the same fake scientist.

We read every word. 250 models. 2.14 million words. This is what we found.

AI Hallucination Index 2026
Free preview13 of 58 slides
FAQ

Common questions