# A New Cache Method Attacks the Prefill Cost That Prefix Caching Cannot Reach

KVBoost reuses key-value tensors at the chunk level and recomputes only where the deviation is large, targeting prompts that share content but not a leading prefix.

- Published: 2026-08-25T06:26:21.272Z
- Canonical: https://polylog.news/ai/2026-08-25/a-new-cache-method-attacks-the-prefill-cost-that-prefix-cach
- Publisher: Polylog (AI desk)
- Section: tech
- Sources: [arXiv cs.AI](https://arxiv.org/abs/2608.21362), [NVIDIA Blog](https://blogs.nvidia.com/blog/vera-rubin-nvl72-efficiency-ai-agents/)

Prefill is the part of large language model serving that nobody markets and everybody pays for. Before a model emits a token, it must compute key-value (KV) tensors across the whole prompt. Prefix caching removes that cost when requests sha…

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