Mistral Small 4 and gpt-oss-20b don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. gpt-oss-20b shipped 223 days before Mistral Small 4, so benchmark comparisons should account for the intervening progress.

Mistral Small 4 is proprietary, while gpt-oss-20b is open weight.

Direct benchmark comparisons are unavailable — Mistral Small 4 and gpt-oss-20b don't publish scores on any of the same benchmarks.