Mistral Small 3 24B vs Step-3.5-Flash

Mistral Small 3 24B

Mistral AI

Mistral Small 3 is a 24-billion-parameter open-weight language model from Mistral AI, released in January 2025 as an update to the Mistral Small line with targeted improvements to instruction-following, multilingual reasoning, and structured output quality. Released under Apache 2.0, it was designed for deployment on a single high-VRAM GPU, continuing Mistral's focus on practical efficiency over maximum scale. The model became a widely-used option for teams building internal tooling, customer-facing applications, and local inference pipelines that needed strong general capability without the operational overhead of larger models.

StepFun

Step-3.5-Flash, released by StepFun on February 2, 2026, is a Mixture-of-Experts large language model with 197 billion total parameters and approximately 11 billion active parameters per inference. It features a 256K token context window using a 3:1 sliding-window-to-full-attention ratio, processing 100–350 tokens per second. Step-3.5-Flash targets agentic tasks, coding workflows, and open-source deployments requiring frontier reasoning capabilities with efficient inference, under an Apache 2.0 license.