Devstral Small 2 (24B) and GPT-5.1-Codex-Max don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. GPT-5.1-Codex-Max shipped 20 days before Devstral Small 2 (24B), so benchmark comparisons should account for the intervening progress.

Devstral Small 2 (24B) is open weight, while GPT-5.1-Codex-Max is proprietary.

Direct benchmark comparisons are unavailable — Devstral Small 2 (24B) and GPT-5.1-Codex-Max don't publish scores on any of the same benchmarks.