DeepSeek V2.5 and Grok 4 Fast don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. DeepSeek V2.5 shipped 365 days before Grok 4 Fast, so benchmark comparisons should account for the intervening progress.

DeepSeek V2.5 is open weight, while Grok 4 Fast is proprietary.

Direct benchmark comparisons are unavailable — DeepSeek V2.5 and Grok 4 Fast don't publish scores on any of the same benchmarks.