DeepSeek V4 Pro 0813 vs Claude Fable 5 on DeepSWE: Cost, Coding, and Routing

Together AI · 1 week ago · 33 ● 2 sources

DeepSeek V4 Pro 0813 and Claude Fable 5 were tested on DeepSWE, a software engineering benchmark, revealing a 90x cost difference ($0.24 vs $21.63 per rollout) with Fable leading 69.7% to 62.8% on first attempt but Pro matching or exceeding Fable at higher retry counts. A cascading strategy—running Pro first and escalating to Fable only on failures—achieves 82.7% accuracy at $8.28 per task, outperforming either model alone by 13 percentage points while costing 62% less than Fable standalone. The models disagree on 0.39 correlation, making them complementary: Fable excels in Rust and data serialization while Pro handles concurrency and stateful reactivity better.