Explanation of RAM in Activity Monitor?

Discussion in 'Mac Basics and Help' started by combat, Jan 19, 2010.

  1. combat macrumors member


    Dec 13, 2009
    Dallas, Texas

    I was hoping somebody could help explain to me what each piece of this chart is showing. Lately my Macbook 2.2 GHz and 1GB ram has been acting more sluggish. I know a solution would be to add more RAM, which I plan too. But while researching the problem I would like to figure out what this means about my RAM usage.
  2. mbestel macrumors member

    Jan 17, 2010
    Memory usage


    I works something like this:

    Free: memory that is not in use
    Wired: data that cannot be moved to the page file on disk. This must stay in RAM.
    Active: this data is in RAM and has been used recently
    Inactive: this data is in RAM but has not been used recently. When another application needs memory and there is none free, this will be swapped to the page file.

    Hope this helps.


  3. angelwatt Moderator emeritus


    Aug 16, 2005
    From the Activity Monitor Help menu (whodah thunkit):
    • Wired: Wired memory is information that can’t be cached to the disk, so it must stay in RAM. The amount depends on what applications you are using.
    • Active: Active memory is currently in RAM and actively being used.
    • Inactive: Inactive memory is no longer being used and has been cached to the disk. It will remain in RAM until another application needs the space. Leaving this information in RAM is to your advantage if you (or a client of your computer) come back to it later.
    • Used: Used memory is being used by a process and is not immediately available.
    • Free: Free memory is not being used and is immediately available.
    • VM size: Virtual memory, or VM, is hard disk space that can be used as memory. VM size is the amount of disk space being used as memory. Mac OS X can use more memory than the amount of physical RAM you have. A hard disk is much slower than RAM, so the virtual memory system automatically distributes information between disk space and RAM for efficient performance.
    • Page ins/outs: The number of times Mac OS X has moved information between RAM and disk space.
  4. DewGuy1999 macrumors 68040


    Jan 25, 2009
    From Activity Monitor help:
    VM, or virtual memory, is hard disk space that can be used as memory. Wired memory is currently in use and cannot be swapped for virtual memory. Active memory is currently in use, but can be swapped for virtual memory. Inactive memory has been used, and can be swapped. Free memory is immediately available.
  5. combat thread starter macrumors member


    Dec 13, 2009
    Dallas, Texas
    Yah, but you guys are much more helpful. Thanks everyone, that cleared everything up!
  6. tobysnelgrove macrumors newbie

    Jan 21, 2010
    slow macbook pro

    I have 4 gig of ram and am finding my compute slows real fast ... pages ins and outs 2.08 gig / 1.69.
    I am only watching a hockey game on Safari and my sats are
    free 83 mb
    wired 753 mb
    active 2.18
    inactive 1.0 gig
    used 3.92

    when I start processing raw images, the performance sucks.

    I shut down most all my other programs and keep the number of images I am processing minimal yet speed sucks.
    Anyone have any ideas?
  7. baslotto macrumors regular

    Feb 13, 2007
    So just asking the computer would have saved him a whole thread about it... ;D
  8. DewGuy1999 macrumors 68040


    Jan 25, 2009
    I think you need more RAM. My understanding is that page outs should be 20% or less of the amount of page ins.

Share This Page