DeepSeek V3.1 and GPT-5.6 Terra don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. DeepSeek V3.1 shipped 309 days before GPT-5.6 Terra, so benchmark comparisons should account for the intervening progress.

DeepSeek V3.1 is open weight, while GPT-5.6 Terra is proprietary.

Direct benchmark comparisons are unavailable — DeepSeek V3.1 and GPT-5.6 Terra don't publish scores on any of the same benchmarks.