Memory Usage

in Genius Bar edited January 2014
For some reason, my memory usage always seems to be much higher than it should be. I check on activity monitory, and the active processes tab adds up to be much less than the active ram used number it gives me.

is there something wrong with my comp, and is there a reliable way to flush the ram once and a while?

or maybe my terms are mixed up. whats the difference between active and wired ram?


  • Reply 1 of 3
    Memory usage is a difficult thing to understand, and it sounds like you are running into this problem. Rather than looking hard at this, instead take a look at the page-outs number. This is a little tricky as well, but the short of it is that you don't care about the absolute numbers, but rather how they change.

    The other note is that you want as much possible memory to be used as possible, but don't want page-outs (which mean that the system ran out of memory).
  • Reply 2 of 3
    From the Activity Monitor help file:

    Wired: Wired memory is information that can’t be cached to 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 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 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 memory being used. 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 must automatically distribute 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.
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