LLM KV Cache Quantization

What KV-cache quantization buys and costs when serving LLMs: how lower-precision keys and values trade memory budget against measured output quality.

The KV Cache Mirage: 1.9x That Frees Nothing

Every team trying to wring the best economics out of a serving stack is reaching for the same lever, and a lot of them are falling for the same trap. It does not matter whether the model lives in a single box (the 8-way B300 nodes reaching general availability right now carry roughly 2.3 TB of HBM) or spans an NCCL fabric across many of them: context and concurrency are capped by the KV cache, so KV-cache optimization is where everyone goes looking for free capacity. When a library advertises more KV tokens at no cost, it lands on the most expensive bottleneck in the deployment. The instinct to take that offer is correct. The discipline to measure it before you build a capacity plan on it is the part this note is about. ...