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Claude 3.5 Sonnet vs gpt-oss-20b

2 vs 0 benchmarks won

Anthropic
Claude 3.5 Sonnet
OpenAI
gpt-oss-20b
Overview
CompanyAnthropicOpenAI
Release dateJun 20 2024Aug 5 2025
Model type
Open sourceNoYes
Specifications
Parameters
Context window
Benchmarks
Science reasoning
GPQA Diamond
59.4%
Software engineering
SWE-Bench Verified
33.4%
Multimodal understanding
MMMU
Timeline
Release gapClaude 3.5 Sonnet shipped 411 days before gpt-oss-20b

Which is better: Claude 3.5 Sonnet or gpt-oss-20b?

Claude 3.5 Sonnet leads gpt-oss-20b on 2 of the tracked benchmarks (GPQA Diamond, SWE-Bench Verified, MMMU). Claude 3.5 Sonnet shipped 411 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 3.5 Sonnet 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 3.5 Sonnet released?
Claude 3.5 Sonnet was released by Anthropic on Jun 20 2024.
When was gpt-oss-20b released?
gpt-oss-20b was released by OpenAI on Aug 5 2025.
Is Claude 3.5 Sonnet or gpt-oss-20b open source?
gpt-oss-20b is an open-source / open-weight model released by OpenAI. Claude 3.5 Sonnet is a proprietary model released by Anthropic.

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