Most of Qwen3.8-Flash-Next's KV cache can live in system RAM, giving 1M context on three 3090s.

An r/LocalLLaMA builder patched vLLM to offload most of the KV cache to host RAM and reports 1M context on 3x RTX 3090: about 80 tok/s at short context, dropping to roughly 60 once QSA hits its 2,048-token budget and then staying flat as context grows, ~150 tok/s at four concurrent requests, 3,701 tok/s prefill at 248K. The argument is architectural rather than a trick. Decode speed is bound by the per-step memory read, and in the qwen4_exp family the layers reading the whole cache every step are sparse enough that the rest can sit across PCIe. Patches and model on the author's HF page; the claim generalizes to any qwen4exp-based model.