Virtual Memory

Discussion in 'macOS' started by amholl, Dec 14, 2005.

  1. amholl macrumors 6502

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    Boston
    #1
    Why do some apps, such as activity moniter and firefix, take up somuch virtua memory? Is there a way to stop that? Is it bad? BTW, I have 768 MB of RAM and the most intensive thing i do is play jedi academy multiplayer. THX
     
  2. dmw007 macrumors G4

    dmw007

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    #2
    Why they use so much virtual memory is beyond me. Virtual memory in itself is not a bad thing- it is there to help improve your Mac's performance.
     
  3. mad jew Moderator emeritus

    mad jew

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    #3
    Activity Monitor claims that processes are using up large amounts of Virtual RAM when in fact they may not necessarily be doing so. I wouldn't worry about it personally, it's just the way OSX works. :)
     
  4. amholl thread starter macrumors 6502

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  5. dmw007 macrumors G4

    dmw007

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    #5
    There is usually no need to question Mac OS...it knows what its doing. :)

    Now windows on the other hand... :rolleyes: ;) :)
     
  6. mad jew Moderator emeritus

    mad jew

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    #6
    I suppose a better way of putting it is that OSX allocates Virtual RAM before it is needed (if it ever is needed). I agree, it's a pretty strange system.



    Yeah, good point. :D
     
  7. MacsRgr8 macrumors 604

    MacsRgr8

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    #7

    It even caches the memory used by an app. So, whenever you have used an app that has used up alot of VM and quit it, alot of that RAM has been "reserved" as inactive, so that if you would like to use that app again, it can use that RAM it has accessed before again. This results in faster loading times etc.
     
  8. bousozoku Moderator emeritus

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    #8
    It would be nice if you could set certain applications as frequently used as a hint to the VM system to release memory for less frequently used applications immediately.

    I haven't really found a problem with VM since 10.4.3 but I'm running a dual 800 with 1.5 GB of RAM and free memory is almost always below 500 MB now.
     

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  9. yellow Moderator emeritus

    yellow

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    #9
    Don't forget.. "Free" and "Inactive" should be slapped together and relabeled "Free".
     
  10. dmw007 macrumors G4

    dmw007

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    #10
    True, these two terms tend to be easily confused.
     
  11. bousozoku Moderator emeritus

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    #11
    Inactive perhaps should be labeled "nearly free" "potentially free" "separated" or "could get back together" since it's still preferred memory.
     
  12. Soulstorm macrumors 68000

    Soulstorm

    Joined:
    Feb 1, 2005
    #12
    1)Why? What problems have you had with virtual memory before 10.4.3?
    2)Actually, even physical RAM is reallocated when an intense process takes place.

    I had worries too, until I tried this thing: On a 1GHz iMac G4 with 768 mbytes RAM I opened unreal tournament 2004, safari, photoshop, and iMovie. I run them simultaneously. I put Safari to download a huge file. Photoshop was left inactive (but still open) I put iMovie to do an export and I played Unreal Tournament 2004. Although the game was sloooooooooooooow, it did run, and I played a whole level of it, even if it performed slow.

    When I closed UT2004, I noticed that none of these programs had quit unexpectedly. Every program was still continuing it's process. So, my worries about OS X's memory management were gone. I did that in OS X 10.3.7.

    And my personal advice to all who worry about VM: If your machine doesn't quit unexpectedly or hung up, there is absolutely no reason to question OS X's virtual memory management!
     
  13. bousozoku Moderator emeritus

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    #13
    Mac OS X's VM system has been problematic from the start. It took quite a long time for them to get it right.

    Anyway, what problems did I have?

    • System stuttered from 10.4 through 10.4.2. Page prediction pre-load/re-load was not working right.
    • Since 10.3.6 VM would suck up all free RAM for no apparent reason and the system would grind to a slow halt.

    It's not that I cared but I have this thing about using my system. With 1.5 GB of RAM and using very little of it, I never expected that I'd run out of memory because the VM had a memory leak that was introduced with 10.3.6. It actually seemed to be much better with 10.3.9. Then, I switched to 10.4 and that sometimes made the system unusable. It was almost as if I had a single-tasking system because trying to use it with multiple applications was problematic. The system would seemingly lock up for 30 seconds at a time trying to figure out what to load and then, loading it, only to find that it wasn't enough. 10.4.3 finally fixed that completely and I've no more bad words for the VM system in Mac OS X.
     
  14. yellow Moderator emeritus

    yellow

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    Location:
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    #14
    Touche <-- accented

    You are very correct (and funny). But for all intents and purposes (or for those idiots out there.. intensive purposes).. :)
     
  15. mkrishnan Moderator emeritus

    mkrishnan

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    Location:
    Grand Rapids, MI, USA
    #15
    Come on, Option-e + e. You can do it. You're better than that.

    Touché.

    Oh, snap.

    :D
     
  16. yellow Moderator emeritus

    yellow

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    #16
    Not on a Windows XP box, smartguy. :p
     
  17. mkrishnan Moderator emeritus

    mkrishnan

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    Grand Rapids, MI, USA
    #17
    XP? Now I know you're better than *that*. :D

    *le sigh* I used to know how to do it in Windows, but I don't remember at the moment.

    I guess I just got served. :(
     
  18. yellow Moderator emeritus

    yellow

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    Oct 21, 2003
    Location:
    Portland, OR
    #18
    Unfortunately.. Active Directory and Blackberry are my bosses this morning..
     

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