Step 5 Preview
Step 5 Preview is an open-weights language model from StepFun, released September 16, 2026. It has 604B parameters (mixture-of-experts, 7B active). The context window is 1M tokens. API price: $1.05 input / $2.99 output per million tokens.
Step 5 Preview is StepFun's flagship sparse MoE model (about 600B total parameters, about 27B active per token) with text, image and video input, released via API on 18 September 2026 with open weights announced for 15 October 2026.
Check it against your own PC →
Can you run Step 5 Preview locally?
Even with 32 GB of VRAM and 32 GB of RAM it is too large to run at a usable speed on a single consumer GPU. Estimates assume 32 GB of DDR5 RAM, a 16K context and llama.cpp-style GGUF quantization. Enter your exact hardware in the live app.
| GPU memory | Verdict | Best quant | VRAM | RAM | tok/s |
|---|---|---|---|---|---|
| 6 GB VRAM | Too large | – | – | – | – |
| 8 GB VRAM | Too large | – | – | – | – |
| 12 GB VRAM | Too large | – | – | – | – |
| 16 GB VRAM | Too large | – | – | – | – |
| 24 GB VRAM | Too large | – | – | – | – |
| 32 GB VRAM | Too large | – | – | – | – |
Ready-made quantizations on Hugging Face: smalinin/Step-5-Preview-GGUF · kefallrain/Step-5-Preview-EXL3-2.4bpw-2xSpark · pb09204048/Step-5-Preview-5layer
Benchmark results
Epoch AI has not published results for Step 5 Preview yet. New models are usually evaluated within days to weeks.
Links
Announcement · Hugging Face: stepfun-ai/Step-5-Preview