OpenAI GPT OSS 20B vs OpenAI GPT-4o

Detailed comparison for LLMs

OpenAIOpenAI

On Guardion's LLM vulnerability Benchmark, OpenAI GPT OSS 20B is the more secure of the two: GPT OSS 20B scores 20.0% and GPT-4o scores 22.8% 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

GPT OSS 20B is the overall winner in this comparison!

Attack Success Rate (lower is safer)

ASR for OpenAI GPT OSS 20B vs OpenAI GPT-4o. Green marks the safer model on each metric. Only the overall score is available for estimated models.

Overall (ASR)

GPT OSS 20B
20.0%
GPT-4o
22.8%

TAP Attack Method (ASR)

GPT OSS 20B
100.0%
GPT-4o
39.6%

Crescendo Attack Method (ASR)

GPT OSS 20B
100.0%
GPT-4o
25.6%

Zero-Shot (ASR)

GPT OSS 20B
100.0%
GPT-4o
3.4%

Key Highlights

  • OpenAI GPT OSS 20B has a lower Overall (ASR).
  • OpenAI GPT-4o has a lower TAP Attack Method (ASR).
  • OpenAI GPT-4o has a lower Crescendo Attack Method (ASR).
  • OpenAI GPT-4o has a lower Zero-Shot (ASR).

Security Profile

Outward is better on every axis.

OverallTAPCrescendoZero-Shot
GPT OSS 20B
GPT-4o
Full security profile
OpenAI GPT OSS 20B
Full security profile
OpenAI GPT-4o

Frequently asked questions

Is OpenAI GPT OSS 20B or OpenAI GPT-4o more secure?

On Guardion's LLM vulnerability Benchmark, OpenAI GPT OSS 20B is the more secure of the two: GPT OSS 20B scores 20.0% and GPT-4o scores 22.8% 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 GPT OSS 20B vs GPT-4o?

GPT OSS 20B has a 20.0% ASR and GPT-4o has a 22.8% ASR — the share of adversarial prompts that succeed across zero-shot, TAP, and Crescendo attacks. Lower is safer.

How were GPT OSS 20B and GPT-4o 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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