Kimi K3 vs Opus 5: Task quality close, K3 2-4.6x cheaper per task
lqiao · x · 2026-07-28
Fireworks AI's lqiao published a comparison of Kimi K3 and Opus 5 on SWE (480), Algorithmic (100), and Terminal (83) benchmarks. Task-level quality is close with Opus 5 on par or better, but K3's per-task cost (serverless pricing) is 2-4.6x cheaper. The study emphasizes task-based cost over token cost as open models tend to be more verbose. Fireworks plans to improve serving efficiency and quality via inference and training optimizations.
Related event: Fireworks Test: Kimi K3 Matches Opus 5 Quality at Fraction of Cost(5 posts)→
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