xAI Grok-4.1 Fast Reasoning vs Google Gemini 3 Flash

Detailed comparison for LLMs

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On Guardion's LLM vulnerability Benchmark, Google Gemini 3 Flash is the more secure of the two: Grok-4.1 Fast Reasoning scores 14.0% and Gemini 3 Flash scores 10.0% on attack success rate (ASR) (lower is better). One or both scores are estimated from public safety evaluations pending a Guardion benchmark run.

Head-to-Head Overview

Gemini 3 Flash is the overall winner in this comparison!

Attack Success Rate (lower is safer)

ASR for xAI Grok-4.1 Fast Reasoning vs Google Gemini 3 Flash. Green marks the safer model on each metric. Only the overall score is available for estimated models.

Overall (ASR)

Grok-4.1 Fast Reasoning
14.0%
Gemini 3 Flash
10.0%

TAP Attack Method (ASR)

Grok-4.1 Fast Reasoning
100.0%
Gemini 3 Flash

Crescendo Attack Method (ASR)

Grok-4.1 Fast Reasoning
100.0%
Gemini 3 Flash

Zero-Shot (ASR)

Grok-4.1 Fast Reasoning
100.0%
Gemini 3 Flash

Key Highlights

  • Google Gemini 3 Flash has a lower Overall (ASR).

Security Profile

Outward is better on every axis.

OverallTAPCrescendoZero-Shot
Grok-4.1 Fast Reasoning
Gemini 3 Flash
Full security profile
xAI Grok-4.1 Fast Reasoning
Full security profile
Google Gemini 3 Flash

Frequently asked questions

Is xAI Grok-4.1 Fast Reasoning or Google Gemini 3 Flash more secure?

On Guardion's LLM vulnerability Benchmark, Google Gemini 3 Flash is the more secure of the two: Grok-4.1 Fast Reasoning scores 14.0% and Gemini 3 Flash scores 10.0% on attack success rate (ASR) (lower is better). One or both scores are estimated from public safety evaluations pending a Guardion benchmark run.

What is the attack success rate (ASR) of Grok-4.1 Fast Reasoning vs Gemini 3 Flash?

Grok-4.1 Fast Reasoning has a 14.0% ASR and Gemini 3 Flash has a 10.0% ASR — the share of adversarial prompts that succeed across zero-shot, TAP, and Crescendo attacks. Lower is safer.

How were Grok-4.1 Fast Reasoning and Gemini 3 Flash tested?

Both were red-teamed with the HarmBench framework across zero-shot, TAP (Tree of Attacks with Pruning), and Crescendo multi-turn attacks, scored by Attack Success Rate.

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