Hunyuan Turbo S

Hunyuan Turbo S, released February 27, 2025, is Tencent's flagship "fast-thinking" model and the first large-scale industry deployment of a Mamba-Transformer hybrid architecture. It pairs Mamba2's linear-complexity long-sequence processing with Transformer attention in a 560B-total / 56B-active mixture-of-experts design, pre-trained on 16 trillion tokens with a 256K context window. An adaptive long-short chain-of-thought mechanism switches between instant answers and deeper reasoning per query, cutting first-token latency by 44% versus DeepSeek R1-style reasoning models.

The honest picture: Turbo S is a speed play, not a reasoning crown — deep-thinking sibling Hunyuan T1 (and later T1-Vision) handles the hardest reasoning, while Turbo S trades some depth for sub-second responses. It is API-only with no open weights, so you are locked into Tencent Cloud pricing and availability. Benchmark parity claims (DeepSeek V3, GPT-4o class) come from Tencent's own reporting and independent LMSYS Arena scores (1356, top-8), which is strong but not chart-topping.