Research2026-09-17

DeepSeek released DeepSeek-V4.1-Flash, a multimodal mixture-of-experts model. It supports contexts up to one million tokens. The model uses a causal encoder-decoder architecture. It activates 16B parameters per token during decode and 8B during prefill. It combines cross-layer KV cache reuse with FP4 KV caching. Global KV cache footprint is 890 bytes per token. Persistent KV cache footprint is one-eighth of DeepSeek-V4-Flash. The model outperforms DeepSeek-V4-Flash on agentic benchmarks. It was pretrained on 45T tokens. Checkpoints are available on Hugging Face.

What changed

DeepSeek-V4-Flash used 4x the global KV cache and 8x the persistent KV cache per token.

What it unlocks

Running long-horizon agents with one million token contexts at lower memory and bandwidth cost.

  • 552B backbone parameters
  • 1M token context
  • 890 bytes per token global KV cache
  • 45T token pretraining corpus

What you need to act on it

  • access to Hugging Face model checkpoint

Sources

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