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Equation 1 · Part 8 · AI Memory Systems and the Bandwidth Wall in Practice: An Advanced Technical Guide

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MKV=2⋅L⋅H⋅dh⋅b⋅s⋅pM_{\mathrm{KV}} = 2 \cdot L \cdot H \cdot d_h \cdot b \cdot s \cdot p
=

What this part means

The expressions on both sides represent the same quantity under the stated assumptions.

Its job in the formula

The equals sign connects the complete expression on the left with the complete expression on the right. Both sides must have compatible units.

The passage around this formula

The key-value cache is the part of a serving system’s memory footprint that a purchasing decision cannot fix, because it does not exist until a request is running. It grows with every generated token, in proportion to context length, batch size, layer count and head dimension, and its lifetime is exactly the lifetime of the request that owns it — arriving and departing unpredictably, at whatever size that request’s conversation happens to reach. A capacity plan sized for the average context length will be wrong for the tail, and a naive contiguous allocator sized for the tail will waste most of its memory on requests that never reach it. with L transformer layers, H key-value heads, dhd_h head…

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Learn the underlying idea

An equals sign says that the expression on its left and the expression on its right have the same value under the stated definitions and assumptions.

Open the illustrated equality: what the equals sign claims guide →

Sources cited in the article section

These citations provide research context; check each source for the exact claim it supports.