Apr 20

When your computer is running a bit slowly, how can you tell if getting more memory will help?  The short answer is that if you have little or no ‘free memory’ or if your ‘page-out’ count is high, then you need more RAM. Here’s how to check those two things on any Macintosh running OS X.

  1. Go to your Applications/Utilities folder. (Click on your desktop so that the finder is active then hold down Apple-Shift-U, this will open your ‘utilities folder.)
  2. Open ‘Activity Monitor’ – it will probably be the top-most application in the Utilities Folder.
  3. Press Apple-1 to make sure that the main window of Utility Monitor is open.
  4. Click on the ‘System Memory’ tab at the bottom of the window. This will display a little pie graph of how much memory you are currently using. It will look something like this:

There are two important items to take note of ‘Free:’ and ‘Page outs:’

Free tells you how much free memory you currently have available to use –  the higher the better.  If you have no free memory you should get more RAM.

A Page out  means your computer has run out of memory and had to use some of the Hard Disk instead of RAM. (This is the equivalent of your brain being too full so you have to write your thoughts down on paper to free up some headspace) This DRAMATICALLY slows down your computer.

To quote from Apple:

Moving data from physical memory to disk is called paging out (or swapping out); moving data from disk to physical memory is called paging in (or swapping in)… Extended periods of paging activity reduce performance significantly; such activity is sometimes called disk thrashing.

Tip: Page outs occur when your Mac has to write information from RAM to the hard drive (because RAM is full).  Adding more RAM may reduce page outs.


Some Examples:

Here’s a mac with plenty of RAM (12G) – lots of Free RAM (green) and zero Page outs.

Here’s a mac with just enough RAM (8G) – a relatively little Page out Count (339MB) and some free memory (green).

Here’s a Mac that needs more RAM (it only has 640M!) – note the High Page Out Count (1010524) even though it currently has some ‘free’ RAM.

This Mac definitely needs some more RAM! Practically no free memory  AND High Page-out Count. (1GB!)  Performance will be suffering badly. I would add at least another 4G Ram, maybe 8G more to bring it up to 12G.

In OSX Leopard rather than giving a ‘count’ of page in and page outs, it gives a size in GB  of the amount of RAM that has been paged in or out. The numbers are smaller but the same principals apply.

In OSX Lion there is a new entry called ‘Swap Used’. (See the last picture above). This  is a count of how much Disk Space your computer is using as RAM and it’s a good rough estimate of the minimum amount of  extra RAM you need. Eg If your Swap used is 4G then get AT LEAST 4G more RAM.

Where to buy more RAM.

If you do need more memory  I recommend buying it from Crucial. They have good prices and reliable RAM. I’m in Australia and it usually arrives in about a week. They have a great memory lookup tool for all Apple Computers where you choose your model and it shows you exactly what memory you need.  The memory chooser tool looks like this:

First choose ‘Apple’ where it says ‘Choose Manufacturer’

Secondly select your mac when it says ‘select product line’ (e.g. iMac or Macbook etc)

Finally select the exact model (e.g. Early 2011 i7 27″ iMac”)

It will then show you the options you can buy.

Another reliable source of Mac RAM is macsales.com, go for their OWC RAM.



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119 Responses to “Does my mac need more memory?”

  1. can u explain step by step how i can find how much mmeory i have left i cant seem to get it.

  2. Lola says:

    My Page ins/outs is 104,797/0
    How do I fix this?
    It keeps saying my startup disk is full, fut I have 562.50 MB Free. my VM size is 11.40

  3. Christine says:

    My stats are similar to Lola’s, and I’m a novice as managing disk space/memory.

    Free: 534.94 MB
    Page ins/outs: 42,436/0

    Clearly, my HD is full, but what can I do to improve processing speed? Will adding RAM help at all? Do I need a whole new computer to solve the HD space problem?

    I have an iMac (Late 2006) with 2 GHz Intel Core 2 Duo processor
    1 GB 667 MHz DDR2 SDRAM
    Running OS X 10.4.11

    Your advice would be MUCH appreciated. I want to upgrade to Snow Leopard, but I don’t want it to get any slower.

  4. admin says:

    Christine, this is not your hard drive space we are looking at but you computers RAM – the memory it uses to run programs and so on.

    If it says ‘your startup disk is full’ it’s talking about your Hard Disk – where it stores movies and music and pictures and so on.

    See this article: http://macintoshhowto.com/hardware/how-to-free-up-some-hard-disk-space.html

  5. Reuben says:

    thanks for the great information.
    Mine appears to be a no brainer with only 512MB 667 Mhz RAM. The readings are showing as follows;
    Free space between 8 and 12MB with page in/out reading of 973200/581084 the in number moved about 40 in 2 minutes.

    Where is the best place to buy reliable quality RAM that I can install myself. I understand this old iMAC desktop has an empty memory slot thus meaning I have the ability to add more RAM. What do you recommend and who should I purchase more from?
    should I
    1/ just increase the 512RAM in the current memory slot
    2/ add more RAM into the empty memory slot
    3/ remove the 512 and fill both memory slots with more RAM.

    you advise would be appreciated.



  6. Sean says:

    I’m totally perplexed. My 2010 mac pro 6-core has 16GB of ram and I’m paging out. Current apps are Adobe Lightroom (real mem 2.36GB) and Photoshop (real mem 3.3GB). There’s 4GB of inactive ram and usually more yet I’ve done 6GB of paging out in the past few days. Confused. VM is 235GB

  7. robert says:

    Sean, I’m in a similar boat, and I’m totally confused.

    I’ve got 12GB of RAM, and since my last reboot, I haven’t run anything but Mail, Safari, and a couple of other small items, with my free RAM never dropping below 9GB.

    But I’ve got about 1GB of page outs. Can anyone explain this?

  8. admin says:

    Sean and Robert… yes that is strange behaviour – Page outs with lots of free RMA. It seems that there could be a problem with Snow Leopard Memory use. Check out this thread: http://forums.macrumors.com/showthread.php?t=875202
    I say seems because I haven’t seen this myself – I only just googled it then.

    This may be fixed in the latest Snow Leoopard 10.6.5 so I can only suggest you update to 10.6.5 and see if that fixes it.

  9. fluke says:

    just added a ssd (flash drive) in place of my hd.
    my computer if flying now.

  10. al says:

    I upped from 2 to 4 on my macbook recently, but the green free stays small. I guess I now have a big blue inactive, but the machine doesn’t work any faster. Should i goto 6? or will it just give a bigger blue inactive?

  11. ben says:

    Before rushing out to upgrade your ram, use onyX (free from apple – do a google search) to fix permissions and run maintance. (you can also repair permissions through the dik utility first aid tool which is in the utility folde, which itsel is in the applications foder.). Fixing permission may appear to freeze for ages (an hour) – but let it finish, reboot and away you go.

    you should do this as often as everytime you intstall a third party app, as they can reek havok with your perissions, making your mac grind to a slow and painful death.

    after this your mac should run as quick as it did when you bought it.

    if not- upgrade ram… but iif you just go ahead and get better ram without sorting out the underlying issues with permissions you will neve get your machine as fast as it should and cold be.

    hope this helps

  12. Molly says:

    I don’t know if this is related to RAM, but I’ve been having this problem for a few weeks now and no other Mac users that I’ve asked have ever faced this. But whenever I try watching a video from the internet, it almost always freezes. BUT the audio still plays fine. It used to only be with Youtube videos, but now almost any internet video will freeze. Could it be because I need more RAM? Please help!! Thank you :)

  13. lolly says:

    I’ve got a MacBook 6,1
    I want to buy and install Photoshop but the system requirements are 2GB + extra during installation….
    My Mac only had 2GB to start with…I’ve just checked the System Memory and it says I only have 192.3MB free….
    Do I have to purchase more RAM before I buy Photoshop? I know it may sound dumb…but how do I add more RAM to it…does it have to be done by a Mac technician?

  14. Meto says:

    I have a problem with my mac pro. All my files and folders been transfered to an external memory but it still shows free memory only 1 gb and used 69gb. Please if any one can help.

    Thank you,

  15. Reem says:

    Hi, i’ve just purchased my first Mac and i mostly use my computer for school. So my university offers microsoft programs for free. but when i tried installing it, it stopped at a certain point and then it says theres zero kb available..
    what exactly does this mean i need to do?

  16. Very informative article. Thank you. However, it still does not explain the issue I am having and why I stumbled onto this post. For the past week I have been trying to update my OS from 10.6.6 to 10.6.7. I cannot get there through the standard route–using “Software update” in the Apple menu because I get an error message telling me there is not enough free space on my disk. When I check Activity monitor it shows I have 5.2 GB free and 0 page outs.

    I am (I think) able to circumvent this problem by downloading the update directly from Apple (it is downloading now) and I plan install it from my desktop. I do not understand why I am getting that message or what to do about it.

    Signed, Stumped at the end of the road in Costa Rica.

  17. karlina says:

    my mac says that i no memmory but i keep on deleting stuff…but it stills says”no memory”help if you can reply very soon!

    • admin says:

      Deleting files doesn’t free up more memory, it frees up more Hard Drive space.
      Quitting running programs or re-starting your computer frees up more memory.

      Files are like your filing cabinet, where you store information long term. Memory is like your desk space, where you work on things. Free memory is like free space on your desk. Pulling files out of your filing cabinet and putting them in the bin won’t give you more desk space. Getting a bigger desk (more memory) or putting away what’s on your desk (quitting programs) frees up desk space.

  18. Bruno says:

    I just put in an extra 8GB of Ram in my G5 Mac Pro. It previously only had 2 GB – so that should bring it up to 10 GB. When I oprn about this Mac – it tells me it only has 2GB of memory. Is there a way to find out exactly how much Ram my computer now has?

  19. my mac says that i no memmory but i keep on deleting stuff…but it stills says”no memory”help if you can reply very soon!

  20. Blackbird says:

    I have a 4gb Macbook Pro 2010 13″ 2.66 ghz. While I have no programs open, or nothing running in the background, is it normal to have the Used memory at 1.3gb? Seems kinda high to me! I’ve had computers with only 2gb and ran things just fine, but if my MBP is using 1.3 idle, thats not right. I’ve had issues with freezing too, which sounds like it might be a bad memory issue?

  21. Sheila says:

    My “System Memory” tab says I have 665MB of free space but when I go to disk usage it says I have completely full and have no free space. My computer won’t even let me save a file of homework. I dont know what to do!!!!!

  22. gh says:

    I came across this forum while searching to try and find why my Macbook runs hot and uses battery fast. This only occurs some of the time. From checking the Activity Monitor I noticed that Parallels (Windows emulator) is using 100% of my available memory. I assume that all other programs create pageouts. I see nobody has mentioned Parallels so it may not be the problem but I thought I’d throw it out. I don’t use Parallels a lot so I may uninstall it as I think it is loading on its own sometimes, depending on what work I’m doing.

  23. Mark says:

    I doubled my RAM to avoid creating lots of swap files. It helped, but I still create swapfiles even though I have 8BG of RAM and I never use more than 6GB. Shutting off the Apple Dynamic Pager did stop the computer from creating swap files in OS 10.6, but the Wired Memory displayed in Activity Monitor gradually grew to sizes I have never seen before. Using iFreeMem did nothing to convert Inactive Memory or the increased Wired Memory back into Free Memory. So far my best solution for avoiding slowdowns from swapping is to just restart the computer every week or so.

  24. Luke says:

    Hey thanks for this, this is a wonderful article and just saved me TOOOOONS of money, your awesome man!

  25. Greg says:

    Upgraded my ram in my MacBook pro to 8gb from the standard 4…. No noticeable difference in performance… Upgraded the Hd to an SSD…. And now it flies ;)

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