seeing how much RAM an app is using in OSX..?

Posted:
in macOS edited January 2014
hey all,

in OS9 i could easily work out how much RAM an app was using by checking in the 'About This Mac' window, but how do i find the same information regarding RAM in OSX?

Thanks all

Comments

  • Reply 1 of 3
    mr. memr. me Posts: 3,219member
    Quote:

    Originally posted by spiers69

    hey all,

    in OS9 i could easily work out how much RAM an app was using by checking in the 'About This Mac' window, but how do i find the same information regarding RAM in OSX?

    Thanks all




    MacOS X is not MacOS 9. Your question is a System 7 through MacOS 9 question. It has nothing to do with MacOS X. The new OS allocates memory on an as needed basis. Its memory map is unified between real and virtual memory, giving each task a continuous memory space. With MacOS 9, memory is allocated up to the limit set in Get Info. The memory map is not unified between real and virtual memory. If you turn on virtual memory, all real memory must be mirrored in virtual memory.
  • Reply 2 of 3
    Well thanks for putting me straight. I guess that would partially explain why apps crash so less frequently in OSX. Thanks again.

    Thinking about it, i've got another question now...

    if i were to open stacks of applications all at once, would it get to the point where there'd no longer be enough RAM to run them? I'm presuming it would, or would it split my RAM (only 256mb) into tiny segments for each app, and they'd all just run REALLY slowly???

    Thanks for your time
  • Reply 3 of 3
    to try and clarify what Mr. Me said:



    MacOS X uses memory very differently than MacOS 9. Information on the memory useage can be found either through the command line program "top" or through the Activity Monitor, but I will have to strongly caution you o find a good primer on how to interpret memory usage in a unix environment as it can be very anti-intuitive (ideally all your memory should be occupied, even if you are not actively using it, and MacOS X is pretty good at approaching that).



    How memory is allocated is also an interesting topic and there is a very smart algorithm that controls this, trying to keep your computer at its most responsive (apparently 10.4 is even more successful with large amounts of memory). The system will actually remove sections of memory that aren't actively being used, and replace them when they are needed. This "swapping" does cost a bit of time, but allows for a lot more flexibility (and as long as you are not starved for memory is actually faster).



    Now, if you only have 256MB, then I would encourage you to get more memory. MacOS X's "sweet spot" is somewhere north of 300MB, and most people figure that it is best to go for 512MB (more being mildly better).
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