GPT OSS 20B vs Claude Opus 4

Compare GPT OSS 20B by OpenAI against Claude Opus 4 by Anthropic, in 2 community votes, claude opus 4 wins 100% of head-to-head duels, context windows of 131K vs 200K, tested across 35 shared challenges. Updated February 2026.

In 2 community votes, Claude Opus 4 wins 100% of head-to-head duels. Claude Opus 4 leads in Web Design. Based on blind community voting from the RIVAL open dataset of 2+ human preference judgments for this pair.