xAI Grok-4.1 Fast Reasoning vs xAI Grok-2

Detailed comparison for LLMs

xAIxAI

On Guardion's LLM vulnerability Benchmark, xAI Grok-4.1 Fast Reasoning is the more secure of the two: Grok-4.1 Fast Reasoning scores 14.0% and Grok-2 scores 46.0% 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

Grok-4.1 Fast Reasoning is the overall winner in this comparison!

Attack Success Rate (lower is safer)

ASR for xAI Grok-4.1 Fast Reasoning vs xAI Grok-2. 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%
Grok-2
46.0%

TAP Attack Method (ASR)

Grok-4.1 Fast Reasoning
100.0%
Grok-2
100.0%

Crescendo Attack Method (ASR)

Grok-4.1 Fast Reasoning
100.0%
Grok-2
100.0%

Zero-Shot (ASR)

Grok-4.1 Fast Reasoning
100.0%
Grok-2
100.0%

Key Highlights

  • xAI Grok-4.1 Fast Reasoning has a lower Overall (ASR).

Security Profile

Outward is better on every axis.

OverallTAPCrescendoZero-Shot
Grok-4.1 Fast Reasoning
Grok-2
Full security profile
xAI Grok-4.1 Fast Reasoning
Full security profile
xAI Grok-2

Frequently asked questions

Is xAI Grok-4.1 Fast Reasoning or xAI Grok-2 more secure?

On Guardion's LLM vulnerability Benchmark, xAI Grok-4.1 Fast Reasoning is the more secure of the two: Grok-4.1 Fast Reasoning scores 14.0% and Grok-2 scores 46.0% 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 Grok-2?

Grok-4.1 Fast Reasoning has a 14.0% ASR and Grok-2 has a 46.0% 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 Grok-2 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.

Related Comparisons