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Equation 8 · Part 1 · AI Memory Systems and the Bandwidth Wall in 2035: Scenarios, Signals, and Falsifiable Predictions

Symbol H_kv

HkvH_{\mathrm{kv}}
HkvH_{\mathrm{kv}}

What this part means

HkH_kv is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.

Its job in the formula

HkH_kv is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.

The passage around this formula

Fact. The memory a transformer must hold for one in-flight generation — its key-value cache — grows linearly in exactly the variables that make serving expensive: sequence length and batch size. For a model with L layers, HkvH_{\mathrm{kv}} key-value heads, head dimension dhd_h , sequence length S , batch size B , and p bytes stored per element, the cache occupies approximately

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Learn the underlying idea

A subscript is a label attached below a symbol. It often selects a time step, component, category, or member of a sequence.

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Sources cited in the article section

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