Sierra RAM management question.

Discussion in 'macOS Sierra (10.12)' started by elf69, Jan 19, 2017.

  1. elf69 macrumors 68020


    Jun 2, 2016
    Cornwall UK
    I have and love my old 2010 macbook.

    I recently upgraded the RAM to 8GB from 4GB.

    With 4GB the monitor app showed 3.36GB ram used but only 2.4GB in use by apps. with varying swap file

    Now have 8GB monitor app shows 5.36GB ram used with 4.11GB used by apps. but no swap file.

    Same apps open as usual here at work.

    Not causing a problem but why use more ram?
    it because with more ram it needs to empty it less often so appears to use more than before as more spare ram to play with.

    just curious.

    Machine running much smoother with 8gb and less pausing and beachballs than with 4gb not that had too many before but I am happier now how it runs.
  2. maflynn Moderator


    Staff Member

    May 3, 2009
    Basically free ram is wasted ram, so OS X has more memory to use and it does. No swap file is a really good thing since disk space is much slower then ram, so when the system keeps more information in ram, the better you are.
  3. keysofanxiety macrumors G3


    Nov 23, 2011
    As a general rule of thumb since at least Snow Leopard: the more RAM OS X has at its disposal, the more it'll utilise/cache to speed up application launches and increase general performance.

    It has much better memory mamangement than Windows... where you're screaming for it to use the extra 8GB RAM you've just put in, yet it insists on partly paging to disk first when opening every single application. I've got the RAM free, Windows!! So much available! Just throw the application into there! (ノಠ益ಠ)ノ彡┻━┻

    (sorry, got a bit derailed)
  4. elf69 thread starter macrumors 68020


    Jun 2, 2016
    Cornwall UK
    thanks guys.

    surprising the difference really 4 to 8.

    boot is faster and zero pauses and beachballs so far.
  5. Daniel Reed macrumors 6502

    Daniel Reed

    Sep 9, 2016
    San Francisco
    What really surprising is the faster Sierra experience by moving from 16GB to 32GB w/ the same number of total memory modules. For me, 10.12.2 seems optimized for 32GB & 64GB memory configurations.
  6. h9826790 macrumors G5


    Apr 3, 2014
    Hong Kong
    TBH, I really don't know how Sierra managing RAM. The following capture is my normal usage.
    Screen Shot 2017-02-22 at 05.28.02 copy.jpg
    Memory pressure in green. More than 20GB is using as cache (usually around 24GB). However, also have ~9GB swap in use (it usually vary at 10GB level). I am not complaining anything. Just feeling interesting that the system choose to use 10GB swap but not release some RAM from cache.
  7. robeddie Suspended


    Jul 21, 2003
    Agreed! I see this kind of thing occasionally as well. I'd love to hear what all these 'experts' who say mac os is so great at memory managment when you have gobs of ram, plenty of free ram, and it still occasionalliy swaps to disk. In your case, 10gb of swap!!!
  8. KALLT macrumors 601

    Sep 23, 2008
    Swap is not undesirable and certainly not avoidable, unless you want your system to force-quit programs (like on iOS) or grind to a halt. The system does not throw out data from memory until it actually needs to, it will prefer to manage the available memory instead and cache, compress or write to disk as needed, based on what the user and the system require. Paging out is just one of the tools it has at its disposal, just as maintaining a large cache of inactive memory is.

    In my opinion, the system does a very good job at preventing memory-related slow downs and using the available memory for responsiveness.

Share This Page

7 January 19, 2017