Across 19 shared benchmarks, GPT-5.6 Sol scores higher on 18 and Kimi K2 Instruct on 1. The widest gap is browsecomp, where GPT-5.6 Sol scores 90.4 against 14.1. Kimi K2 Instruct is the cheaper of the two on tracked API pricing ($0.60 against $4.00 per million input tokens).
Best tracked score per model per benchmark (default configuration; source-attributed). ↓ marks lower-is-better metrics. Open either model for its full surface, provenance and pricing. Quoted rates are the price-setter row we currently track for each model — its direct or vendor-official listing where one exists (direct, direct), otherwise the lowest tracked offer.