StepFun's Step 5 Preview matches Kimi K3 at ~2.8x lower cost per task

ArtificialAnlys · x · 2026-09-22

Artificial Analysis estimates that StepFun's new flagship Step 5 Preview (600B total / 27B active parameters, succeeding Step 3.7 Flash) scores 44 on the Intelligence Index — level with Kimi K3 (max) — while costing only $0.72 per task, roughly 2.8x cheaper than Kimi K3's $2.00.

The gap is pricing, not token usage: both models use 164–170M output tokens to run the Index, but Step 5 Preview is priced at $1/$2.70 per 1M input/output tokens vs $3/$15 for Kimi K3. GLM-5.3 (max) costs $2.01 per task for one extra point. MiMo-V2.6-Pro is the only model scoring higher (46) at lower cost ($0.13). Note: Step 5 Preview trails peers on agentic evaluations.

Related event: Step 5 Preview scores 44 on Artificial Analysis: unmatched cost, weak on agents(6 posts)→

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