Since my update to macOS High Sierra my memory is always at 75% even after a fresh startup.

Is it just iStat Menus that shows it this way or is there really only 25% of memory free (out of 8GB) ?

Or is it the memory that is saved for applications ?

What is the difference between:

  • Wired (???)
  • Active (currently in use?)
  • Compressed (not used since longe time?)
  • Free (free...)

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After closing every app I could, here is the result, approximately 50% of RAM. But WindowServer is huge... What is it?

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  • You appear to be running several processes that are using a large amount of memory. What happens when you close the largest ones (WindowsServer, Chrome, etc)? Does the memory usage go down? Also, see this question for a description of the memory names.
    – fsb
    Oct 13, 2017 at 14:52
  • Yes Chrome is crazy, I started to found out what process inside it was using so much and I started by disabling the Offline mode of my Google Drive which was consuming +700MB alone ! Slack also is consuming a lot...
    – ZazOufUmI
    Oct 13, 2017 at 15:27
  • 1
    @StéphaneJ. 700MB is not the issue What is the memory usage without Chrome?
    – mmmmmm
    Oct 13, 2017 at 15:44
  • @Mark if I remove everything, I'm at 50% RAM consumption. But WindowServer is still consuming a lot of "somehting". Check this screen after closing every app I could : imgur.com/a/yhNoi
    – ZazOufUmI
    Oct 15, 2017 at 15:32

2 Answers 2


MacOS will try to use as much memory as it can. Having more RAM will improve performance, but using most of what you have is not in itself a bad thing. MacOS will make room, if it needs to.

This Apple support document tells you what the various attributes mean:

  • Wired Memory: Memory that can’t be compressed or paged out to your startup drive, so it must stay in RAM. The wired memory used by a process can’t be borrowed by other processes.

  • Compressed: The amount of memory in RAM that is compressed to make
    more RAM memory available to other processes. Look in the Compressed Mem column to see the amount of memory compressed for each process.

"Active" is not a term that Apple uses anymore, but it's 'general' memory used by applications. Wired tends to be system memory, which can't be removed because it's critical; and compressed tends to be stuff that's not being used right now, and so can be compressed to save space.

Memory management is: a) more complicated than "water filling a bottle"; b) something the OS is good at, c) something the OS is doing constantly.

  • Additionally, if you look at Memory Pressure in Activity Monitor, the color will be green, orange, or red. If it's green, you're certainly fine and shouldn't worry.
    – Ezekiel
    May 9, 2019 at 23:59

Use Activity Monitor instead of the silly tool iStatMenus. The Ram handling is complxer than that.

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