Back to list
Lv.3

KV Cache

Key-Value Cache

A technique that speeds up AI text generation by storing and reusing past calculation results.

In Simple Terms

KV Cache is a mechanism that speeds things up by reusing past calculation results when a generative AI outputs text one piece at a time. When an AI writes a sentence, it normally has to recalculate the relationships between everything it has written so far, over and over again. This mechanism saves those past results in memory, so the AI doesn't have to repeat the same calculations to generate the next piece of text. It's widely used to make chat AI and similar tools respond faster.

Behind the Name

"KV Cache" combines "Key", "Value", and "Cache" (the term for temporary storage). The name reflects what's actually being saved: the "key" and "value" data used in the AI's internal calculations, held in memory so it can be reused instead of recalculated.

Take a Closer Look!

KV Cache is a mechanism used by large language models and other generative AI to speed up text generation by storing past calculation results in memory and reusing them.
It's a technique that dramatically speeds up the process an AI goes through as it produces text piece by piece.

For example, when an AI writes the sentence "The weather is nice today," it outputs it a bit at a time — first "The," then "The weather," then "The weather is," and so on.
Each time, the AI has to recalculate how the newly generated piece relates to everything it has already output.
The more text there is, the more this calculation snowballs, and the longer it takes.

That's where temporarily saving past calculation results in memory comes in.
This way, the AI doesn't need to redo the calculations for the entire text from scratch every time it adds something new.
As a result, the total amount of computation drops significantly, and the AI's responses come back much more smoothly.

Roughly speaking, it's like how a person continuing a piece of writing doesn't reread everything from the beginning and rethink it all — they just rely on what they already remember and keep writing smoothly from there.
It does use up more memory, but it's a widely used technique for cutting down on AI's response time.