624mb of "Inactive" memory

Discussion in 'Mac Basics and Help' started by wako, Feb 23, 2006.

  1. wako macrumors 65816

    Joined:
    Jun 6, 2005
    #1
    Well I have a powerbook g4 and upgraded the RAM to 1.25Gb


    Anyways, my computer hasnt rebooted yet. I know the simple fix is simply reboot, however I rather not...


    Anyways, here is the issue, I have 624mb of ram that Activity monitor lables as "Inactive." Is there anyway to free the memory other than rebooting? More importantly why is it inactive? I already closed down ALL the programs that I possibly can (Finder simply cant!) and looked at the Activity Monitor and no programs that are running is using that much memory. Why is it inactive anyways?
     
  2. 50thVert macrumors regular

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    #2
    good question....id also like to know the answer
     
  3. calebjohnston macrumors 68000

    calebjohnston

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    Jan 24, 2006
    #3
    click the apple... then restart... and you can stop worry about a total non-issue. if it's the same after a restart, then there might be a problem.
     
  4. Eidorian macrumors Penryn

    Eidorian

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    Indianapolis
    #4
    Inactive memory memory is memory that was called and reserved by OS X. It's no longer being used by any program yet it's still caching what it was used for. It'll automatically be used again for whatever program runs next. "Free" memory is actually very low in OS X after a long time.

    Free memory isn't what you should be worried about. It's Page Outs. Reboot your machine and use it for 15 minutes. Check your page outs. If you're getting a few thousand then you don't have enough RAM.

    http://www.macworld.com/2006/02/features/speedram/index.php

    The Free RAM issue is a topic that's been beaten to death around here.
     
  5. plinkoman macrumors 65816

    plinkoman

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    #5
    why not? [​IMG]
     
  6. Counterfit macrumors G3

    Counterfit

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    #6
    Inactive RAM isn't a bad thing. If you're concerned about RAM usage, consider inactive to be fairly similar to free. If another application needs it, OS X will give it up.
     
  7. wako thread starter macrumors 65816

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    #7
    Thanks you Eidorian and Counterfit for actually posting things that were helpful.
     
  8. gnasher729 macrumors P6

    gnasher729

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    Nov 25, 2005
    #8
    "Free" memory is memory that has never, ever been used since the Macintosh was started. If your Macintosh showed 624 Megabyte of free memory after long use, that would mean you wasted your money on RAM, because it wasn't ever needed.

    "Inactive" memory is memory that was used at some point, but isn't used right now. If you quit a program that used 200 MB of memory, you get 200 MB of inactive memory. Once you start another program, that memory is used again. So if you quit all open applications, having lots of inactive memory is exactly what you should expect. The memory is inactive because you stopped using it.
     
  9. BakedBeans macrumors 68040

    BakedBeans

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  10. Heb1228 macrumors 68020

    Heb1228

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    #10
    You sound like a windows user here. Rebooting should be way down the list of things to do when something isn't working right on your Mac. I know in Windows that's your first troubleshooting step, but this isn't windows. I usually only restart my powerbook after installing OS X system upgrades (like going from 10.4.4 -> 10.4.5).

    If you ask around, I think you'll find its not uncommon for people to go 2 or 3 months without restarting their computers.

    Your inactive memory is still in memory just in case you load the same programs again. If you need it for something else, it will take care of itself. Relax.
     
  11. jadekitty24 macrumors 65816

    jadekitty24

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    #11
    How does it work? I downloaded it and all it does is open the System Preferances.
     
  12. ElectricSheep macrumors 6502

    ElectricSheep

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    Feb 18, 2004
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    Wilmington, DE
    #12
    Developer Article on Memory Management on MacOS X

    You don't have to worry about large values of Inactive Memory

    A breakdown of the three kinds of memory pages that Mac OS X keeps track of:

    •Free Memory: These are memory pages which have not been allocated to any VM address at all. They are immediately up for grabs for any future memory allocation.

    •Inactive Memory: These are allocated memory pages which reside in real memory, but they haven't been used in a while. As such, they can be released and moved to the free page list at any time. There is a caveat; If the page has been modified since the last time it was written out to the backing store (the VM page file), it is 'dirty' an must be written out to disk before being moved into the free page list for re-allocation. This is a performance penalty. If the page has not been modified, it is 'clean', and can be immediately stolen for another allocation. Since the page hasn't been used in a while, the likely-hood that it is 'dirty' is probably pretty low.

    •Active Memory: These are allocated memory pages which reside in real memory and have been accessed recently. They are still eligible for re-allocation, but the likely-hood that these pages are 'dirty' is pretty high. The performance penalty of writing these pages out to the backing store makes them a poor choice, not to mention that their frequent accesses would require them to be paged back into memory often. The result is 'VM thrashing' in which active pages are paged in and out repeatedly. Not a good situation. Its only when free and inactive memory is exhausted should these pages be used.

    •Wired Memory: These pages are specially flagged by the process which allocated them such that they may never be re-allocated and paged out. They will reside in physical memory with their current allocation until the process explicitly un-flags them.
     
  13. wako thread starter macrumors 65816

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    #13


    Actually in Windows there was a way to free up RAM. I was hoping there was a way for OSX as well
     
  14. ElectricSheep macrumors 6502

    ElectricSheep

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    #14
    IMO, its not worth the resources to traverse and explicitly release pages from memory until you actually have a need to reallocate them. Dirty pages would have to be written out to disk (a very expensive operation), and there is no guarantee that they won't be paged right back in (another very expensive operation) if the application which owns them needs to access the page again.
     
  15. Heb1228 macrumors 68020

    Heb1228

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    #15
    Thats the point. Relax. You don't need to. Try your best to stop thinking like a Windows user. :D

    Next thing you'll be asking how you can better arrange the file structure of your iPhoto library...
     
  16. jeremy.king macrumors 603

    jeremy.king

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    #16
    How?
     
  17. Heb1228 macrumors 68020

    Heb1228

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    #17
    I used to have a program that would do it. (Back in my days of using Windows... but we try not to speak about those times...) That was a long time ago before I finally got a computer that knows how to manage its own resources. Is Apple brilliant or what?
     
  18. jeremy.king macrumors 603

    jeremy.king

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    #18
    Actually I was serious in my question - not trying to be sarcastic or facetious. I run Windows 2000 at the client here and seems my running processes and their memory consumption never jive with what Windows thinks is being used, int turn affecting what it thinks is available.

    Would love to know of a way to clean this up in Windows, other than a reboot - my preferred method at the moment.

    Now back on topic...
     
  19. Eidorian macrumors Penryn

    Eidorian

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    Indianapolis
    #19
    http://www.outertech.com/index.php?_charisma_page=index

    Cacheman "seemed" to work at freeing memory. It's free. The paid version just has specil profiles and custom system personalization.

    http://www.outertech.com/index.php?_charisma_page=product&id=7
     

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