Codestral Mamba 7B and GPT-5 nano don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. Codestral Mamba 7B shipped 387 days before GPT-5 nano, so benchmark comparisons should account for the intervening progress.

Codestral Mamba 7B is open weight, while GPT-5 nano is proprietary.

Direct benchmark comparisons are unavailable — Codestral Mamba 7B and GPT-5 nano don't publish scores on any of the same benchmarks.