‍DeepSeek-V4 Flash 0731 is the cheapest model on the entire DeepSWE board: about ten cents a task! GPT-5.6 Luna, a solid upper-tier flagship, runs \$0.61 a task, roughly six times DeepSeek’s price. So the question is not which one wins the leaderboard (Luna, comfortably) but what six-times-cheaper buys you, what it costs you, and whether the two together beat either one alone.We ran DeepSeek-V4 Flash 0731 (max) against GPT-5.6 Luna (max) on all 113 DeepSWE tasks: real, long-horizon feature requests from live open-source repos, four trials each, graded pass/fail by a hidden test suite. That is 900 rollouts in total from the published per-trial records (452 on DeepSeek's side, 448 on Luna's). Every figure below comes from this run, so it can differ from other public scorecards.At a glance

DeepSWE · Head to Head

DeepSeek-V4 Flash vs GPT-5.6 Luna at a glance

Model

Pass@1