Meta Llama 3H 405B vs OpenAI GPT OSS 20B

Detailed comparison for LLMs

MetaOpenAI

On Guardion's LLM vulnerability Benchmark, OpenAI GPT OSS 20B is the more secure of the two: Llama 3H 405B scores 36.6% 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

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

Attack Success Rate (lower is safer)

ASR for Meta Llama 3H 405B vs OpenAI GPT OSS 20B. Green marks the safer model on each metric. Only the overall score is available for estimated models.

Overall (ASR)

Llama 3H 405B
36.6%
GPT OSS 20B
20.0%

TAP Attack Method (ASR)

Llama 3H 405B
GPT OSS 20B
100.0%

Crescendo Attack Method (ASR)

Llama 3H 405B
GPT OSS 20B
100.0%

Zero-Shot (ASR)

Llama 3H 405B
12.9%
GPT OSS 20B
100.0%

Key Highlights

  • OpenAI GPT OSS 20B has a lower Overall (ASR).
  • Meta Llama 3H 405B has a lower Zero-Shot (ASR).

Security Profile

Outward is better on every axis.

OverallTAPCrescendoZero-Shot
Llama 3H 405B
GPT OSS 20B
Full security profile
Meta Llama 3H 405B
Full security profile
OpenAI GPT OSS 20B

Frequently asked questions

Is Meta Llama 3H 405B or OpenAI GPT OSS 20B more secure?

On Guardion's LLM vulnerability Benchmark, OpenAI GPT OSS 20B is the more secure of the two: Llama 3H 405B scores 36.6% 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 Llama 3H 405B vs GPT OSS 20B?

Llama 3H 405B has a 36.6% 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 Llama 3H 405B 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.

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