xAI Grok-4 Heavy vs OpenAI GPT OSS 20B
Detailed comparison for LLMs
On Guardion's LLM vulnerability Benchmark, xAI Grok-4 Heavy is the more secure of the two: Grok-4 Heavy scores 18.0% and GPT OSS 20B scores 20.0% 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 Heavy is the overall winner in this comparison!
Attack Success Rate (lower is safer)
ASR for xAI Grok-4 Heavy vs OpenAI GPT OSS 20B. Green marks the safer model on each metric. Only the overall score is available for estimated models.
Overall (ASR)
TAP Attack Method (ASR)
Crescendo Attack Method (ASR)
Zero-Shot (ASR)
Key Highlights
- xAI Grok-4 Heavy has a lower Overall (ASR).
Security Profile
Outward is better on every axis.
Frequently asked questions
Is xAI Grok-4 Heavy or OpenAI GPT OSS 20B more secure?
On Guardion's LLM vulnerability Benchmark, xAI Grok-4 Heavy is the more secure of the two: Grok-4 Heavy scores 18.0% and GPT OSS 20B scores 20.0% 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 Heavy vs GPT OSS 20B?
Grok-4 Heavy has a 18.0% ASR and GPT OSS 20B has a 20.0% ASR — the share of adversarial prompts that succeed across zero-shot, TAP, and Crescendo attacks. Lower is safer.
How were Grok-4 Heavy and GPT OSS 20B 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.