Family Step · 196B parameters

Step 3.5 Flash

MoE 196B/11B active. 100 tok/s at 128k ctx. #3 by volume on the OpenRouter free tier.

🇨🇳 StepFun·License Apache 2.0·Context 250k tokens·Output February 2026← Catalog

01What it can do

Strengths
  • Fast despite its size
  • 256k ctx
  • Apache 2.0
Limitations to know
  • —118+ GB in Q4
  • —Still little known in the West
Architecture
MoE 196B/11B active · 256k ctx
Training
StepFun. 100 tok/s at 128k ctx.
Ideal for
Fast MoELong context

04Install

Install Ollama for your OS. Check the model and its quantization before downloading. Start with 4096 tokens of context, then check placement with ollama ps. A command below is not proof that a test was run on your machine.

$# HuggingFace : stepfun-ai/step-3.5-flash
⚠
First download: between 2 and 40 GB depending on the selected quantization. Plan for sufficient disk space; a stable connection is recommended. Subsequent launches are instant.

02Required memory

Approximate GPU VRAM required to run this model, including 4k tokens of context overhead. For a longer context, add ~1 GB per 8k-token increment.

Q4_K_M
The lightest, ~5% loss
118 GB
Q5_K_M
Good quality/size compromise
141 GB
Q8_0
Nearly indistinguishable from FP16
210 GB
FP16
Full precision — server use
392 GB
Fallback CPU · If you don't have a GPU, allow 140 GB of RAM minimum to run this model at reduced speed.

What hardware do you need for Step 3.5 Flash?

To run Step 3.5 Flash locally with Q4 quantization, you need about 118 GB of VRAM. An option to compare: BOSGAME M5 128GB / 2TB (Ryzen AI Max+ 395) — this model exceeds this mini-PC's GPU capacity: choose a smaller model or suitable infrastructure.

Current offer: BOSGAME M5 128GB / 2TB (Ryzen AI Max+ 395)
AmazonSee price →

Why this choice? Our complete guide on BOSGAME M5 128GB / 2TB (Ryzen AI Max+ 395) →

Affiliate links — commission possible at no extra cost to you; independent recommendations. As an Amazon Associate, BestLLMfor earns from qualifying purchases.

This model in your private ChatGPT, without the cloud

Too large for your machine? The kit gives you the model that fits in your VRAM

  • Lifetime online access
  • PDF + files
  • Lifetime updates

03Expected speed

Tokens generated per second in Q4_K_M, 4k context. Beyond 20 t/s, reading is comfortable. Below 10 t/s, that's just for testing.

Entry-level
~2t/s
GTX 1650, RX 6600, MBA M2 8GB
Mid-range
~10t/s
RTX 4060, 4070, MBP M3 Pro
High-end
~25t/s
RTX 4090, M4 Max, Radeon 7900