StepFun previews Step 5: 600B MoE with 27B active at $1/$2.7 per M tokens, open weights next month

nemamdsa12 · reddit · 2026-09-21

A Reddit thread discusses StepFun's newly previewed Step 5 model: a 600B-parameter MoE with 27B active, priced at $1/$2.7 per million tokens, with open weights promised next month—apparently skipping Step 4 entirely.

The poster is impressed by its 3D demo, a room-scale model where furniture can be dragged around, and is asking whether anyone has run it on real workloads yet.

Related event: StepFun Launches Step 5 Preview: 600B MoE Rivals Kimi K3 at a Fraction of the Price(15 posts)→

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