Glossary
Cached files
File data macOS keeps in otherwise unused memory so it can open it again quickly.
What it is
Apple describes cached files as files cached by the system into unused memory to improve performance. When an app needs that memory, macOS drops the cache and hands the memory over.
This is why “free memory” on a Mac is often small. Unused memory would be wasted; cached memory is still useful and is released on demand.
Why it matters
A large cached figure is good news, not a problem. Apps that promise to “free up RAM” mostly throw this cache away, which makes files slower to open again.
In Activity Monitor
“Cached Files” under the Memory Pressure graph in the Memory tab.
In iKnowMyMac
“Cached” in the Memory tab breakdown. It is not counted as memory in use.
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