Kimi K3 vs Opus 5: Comparable Task Quality at a Quarter of the Cost
lqiao · x · 2026-07-28
Fireworks AI compared Kimi K3 and Claude Opus 5 based on common business use cases, measuring task-level cost and quality rather than token metrics across SWE, algorithmic, and terminal benchmarks.
The findings reveal that both models deliver very similar task-level quality. However, under serverless pricing, Kimi K3 is 2x to 4.6x cheaper per task. Fireworks plans to further improve serving efficiency and model quality through its own inference and training infrastructure.
Related event: Fireworks Test: Kimi K3 Matches Opus 5 Quality at Fraction of Cost(5 posts)→
More from Models
- BullshitBench update: GPT-6-Astra beats all prior OpenAI models but still trails Anthropic — scaling01 · 2026-09-11
- Astra Scores 83% on GauntletBench, First Computer-Use Agent to Beat Human Baseline — ducha_aiki · 2026-09-11
- Kimi K2.8 Preview rolls out: near-K3 coding performance, 1M context for all tiers — teortaxesTex · 2026-09-11
- Looking for a classifier of software engineering task shapes to pick models per task — StewartalsopIII · 2026-09-11
- DeepSeek V4 Pro API to continue after Sept 2026, billing unchanged — teortaxesTex · 2026-09-11
- DeepSeek V4.1 Flash Hits 98% of GPT-6 Astra's Score at 1.4% of the Cost in Third-Party Benchmark — ayushtweetshere · 2026-09-11