StepFun's Step 5 Preview lands on the Artificial Analysis cost/intelligence frontier at a third of Kimi K3's price
Artificial Analysis (via r/singularity, 47 upvotes)·medium signal
StepFun, not previously a frontier lab, released Step 5 Preview on September 18. Artificial Analysis scores it 44 on its Intelligence Index, matching Kimi K3 max, at $1.00 per million input and $2.70 per million output with a 95% cache discount, 99.8 output tokens per second and a 1M context window. It is closed-source, so unlike the recent Chinese open-weight releases there is nothing to run locally, which is the main caveat on the 'another Chinese lab reached the frontier' framing.