Breaking from China's AI scene: StepFun just dropped Step 5 Preview, and the numbers are wild.
First stat that jumps out: 600 billion total parameters, but only 27 billion active per token. That's the Mixture-of-Experts trick, think of a huge hospital with specialists in every field, but when a patient comes in, only the relevant doctor gets called, not the entire staff.
Second stat, and honestly the bigger deal: a 1 million token context window. That means it can hold an entire codebase, a massive financial report, or a full book in memory while working through it, without losing the thread.
It's not just text either. Step 5 handles images and video too. The target use case is long-horizon agentic work: software engineering, professional knowledge tasks, finance, the kind of jobs that need sustained focus over long stretches, not quick one-off answers.
Pricing is live now at $1.00 per 1M input tokens and $2.70 per 1M output tokens. Not the cheapest on the market, but reasonable given what it's packing under the hood.
The best part? Open weights are scheduled for October 15, 2026. This won't stay locked behind an API forever.
Long-context is quietly becoming the real battleground in AI, and whoever can remember the most, wins the most.
🔗 Original Source & Reference: https://www.marktechpost.com/2026/09/20/stepfun-launches-step-5-preview/
Published automatically via FeedMind AI Content Pipeline.
Top comments (0)