DeepSeek V4.1-Flash uses asymmetric MoE activation and a smaller KV cache to target lower inference cost
DeepSeek introduced V4.1-Flash on September 10 as a 552-billion-parameter mixture-of-experts model with native visual understanding. Its new Causal Encoder–Decoder architecture activates 8 billion parameters while processing input and 16 billion while generating output. DeepSeek says the model needs one quarter of the HBM and one eighth of the SSD storage for KV cache compared with the previous generation. V4.1-Flash is available through the DeepSeek API as deepseek-flash, while retired V4 Flash aliases temporarily route to it for compatibility. At this batch's 06:00 Beijing run, the V4-Pro cutover was still in the future: DeepSeek scheduled all deepseek-v4-pro requests to route to V4.1-Flash from 04:00 UTC, or 12:00 Beijing time, on September 14 until V4.1-Pro launches.

