Having trouble with my RAM, some of it is not in Use

Discussion in 'iMac' started by likwidsolutions, Aug 27, 2014.

  1. likwidsolutions macrumors member

    Apr 17, 2014
    So basically I have 16GB of DDR3 RAM in my Late 2013 27" 3.2GHz iMac. It's worked great up until just recently.

    I seem to run out of memory very quickly, even when I am not running much, or anything at all (except background programs, but they don't take up much memory). Just now I restarted my computer then I left to go to the store; I was gone for about 30 minutes and there was nothing running while I was gone except background programs and it's showing I have less than 10MB Free. It's bothering the hell out of me because I had W8 Bootcamped in but I restored my HDD because I needed more space for Windows (just for gaming), and this memory thing, which I thought a clean restore would fix, but apparently not.

    My Mac recognizes that there is 16GB installed when I click "About this Mac" or go to System Information, but when I run memtest to see my memory and how it's allocated, it looks like 8 GB of my RAM is not in use if I read this correctly. This is what memtest says (I am running it right now and it's not done but it looks like it's only recognizing 8GB.

    Memtest version 4.22 (64-bit)
    Copyright (C) 2004 Charles Cazabon
    Copyright (C) 2004-2008 Tony Scaminaci (Macintosh port)
    Licensed under the GNU General Public License version 2 only

    Mac OS X 10.9.4 (13E28) running in multiuser mode
    Memory Page Size: 4096
    System has 4 Intel core(s) with SSE
    Requested memory: 8555MB (8971374592 bytes)
    Available memory: 8555MB (8971374592 bytes)
    Allocated memory: 8555MB (8971374592 bytes) at local address 0x0000000101000000
    Attempting memory lock... locked successfully
    Partitioning memory into 2 comparison buffers...
    Buffer A: 4277MB (4485687296 bytes) starts at local address 0x0000000101000000
    Buffer B: 4277MB (4485687296 bytes) starts at local address 0x000000020c5e2800

    Running 1 test sequence... (CTRL-C to quit)

    Test sequence 1 of 1:

    Running tests on full 8555MB region...
    Stuck Address : ok
    Linear PRN : ok
    Running comparison tests using 4277MB buffers...
    Random Value : ok
    Compare XOR : ok
    Compare SUB : ok
    Compare MUL : ok
    Compare DIV : ok
    Compare OR : ok
    Compare AND : ok
    Sequential Increment: ok
    Solid Bits : ok
    Block Sequential : setting 111 of 256

    Do you think if I unistalled the RAM and then Reinstalled it, it might just reset this? I tried resetting the PRAM too just to see if that might help, no dice. I am having a little bit of trouble installing W8 but I had a few months where I couldn't install Windows because these Haswell processors are so finicky. But W8 loads much easier than W7, so I have had more luck with that. Last time I just ran the Boot Camp Assistant and it worked fine, this time it wouldn't install on the Bootcamp partition. I tried formatting it in the Windows Setup and that was a no go, I also tried formatting it in Mac OS X to NTFS (I have a driver for NTFS formatting and reading). Still no go.

    Anyways I am more concerned with this RAM stuff because I have been thinking about getting 2x8GB sticks and upgrading to 24GB but if it's not going to use it properly, then it's kind of pointless.

    Any ideas? ANY help would be appreciated as this is starting to drive me crazy. Even with 8GB my computer should not be dropping to less than 100MB of free RAM, especially if all I am running is Safari (with 1 or two tabs). Sometimes I have a ton of stuff open in which case I would expect more RAM to be used. But I am barely using anything at all. I have to free up my memory using an app like every 10 minutes. So yeah is there a way to reallocate RAM, and does anyone know how this might have happened? I thought it might have something to do with VMWare and Windows 8 installed on that because I allocate 8GB for that (but I would assume it only uses that 8GB only if it's running, otherwise it would be kind of pointless). I don't know how my RAM will show up on Windows (if it will allow me to use all 16GB or not). But Mac OS X shouldn't have this problem whatsoever.
  2. chrfr macrumors 604

    Jul 11, 2009
    Memtest can only test the RAM that isn't in use for other things, so this is totally normal.
    Use Activity Monitor to look at where your RAM is being used.
    Unused RAM is wasted RAM so having free memory isn't necessarily a benefit.
  3. rottnjohn macrumors newbie


    May 22, 2011
    silly valley
    Edit your VM's settings and cut the memory back to 4. If you can change it all, it isn't running.
    Are you sure you aren't starting vmware in your Login Items?
    If you change the VM settings, reboot and run memtest, does it think you have 12 or 16G of RAM?
  4. boast macrumors 65816


    Nov 12, 2007
    Phoenix, USA
    Incorrect. Modern operating systems make good use of free memory.
  5. likwidsolutions thread starter macrumors member

    Apr 17, 2014
    yeah I started to realize thatafter I read up more about RAM and how OS X uses that. I also upgraded to 32 gigabytes, which wasn't quite necessary but it has helped a lot.

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