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Claude Opus 4 vs gpt-oss-20b

2 vs 0 benchmarks won

Anthropic
Claude Opus 4
OpenAI
gpt-oss-20b
Overview
CompanyAnthropicOpenAI
Release dateMay 22 2025Aug 5 2025
Model type
Open sourceNoYes
Specifications
Parameters
Context window
Benchmarks
Science reasoning
GPQA Diamond
79.6%
Software engineering
SWE-Bench Verified
72.5%
Multimodal understanding
MMMU
Timeline
Release gapClaude Opus 4 shipped 75 days before gpt-oss-20b

Which is better: Claude Opus 4 or gpt-oss-20b?

Claude Opus 4 leads gpt-oss-20b on 2 of the tracked benchmarks (GPQA Diamond, SWE-Bench Verified, MMMU). Claude Opus 4 shipped 75 days before gpt-oss-20b, so benchmark comparisons should account for the intervening progress.

gpt-oss-20b is an open-source / open-weight model; Claude Opus 4 is proprietary.

Direct benchmark comparisons are unavailable — at least one of these models has not published scores on GPQA Diamond, SWE-Bench Verified, or MMMU.

Frequently asked questions

When was Claude Opus 4 released?
Claude Opus 4 was released by Anthropic on May 22 2025.
When was gpt-oss-20b released?
gpt-oss-20b was released by OpenAI on Aug 5 2025.
Is Claude Opus 4 or gpt-oss-20b open source?
gpt-oss-20b is an open-source / open-weight model released by OpenAI. Claude Opus 4 is a proprietary model released by Anthropic.

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