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.


Note (Jan 2013): I have signed up as a Crucial affiliate partner.

Click here to get 5% off your crucial order (and I get 2% commission)!

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

  1. wayne says:

    I just received this by email,
    look at how high the page in/out count it!


    Time for memory upgrade!

    • HaWook says:

      My Page ins and Page outs are expressed in megabytes (960 and 325, respectively). How can I figure out the actual number?

      Please and thank you.

    • Andrew says:

      The blue section reads ‘Inactive’ for a reason. A program has claimed it, but is not using it. Your mac should page these out because it is essentially empty space. Windows does this as well, its called scrubbing.

      Want proof, go to the apple store and run Activity monitor on one of the showroom macs. There will be tons of page outs despite the fact these macs only have the programs that come with your mac (and your mac was designed to handle without slow downs).

      This is Apple marketing bull trying to make you pay $400 for overpriced RAM. Get iFreeMem and see what I mean, this will page out all inactive memory, essentially turning all your blue memory green and speeding up your Mac.

      • Anna says:

        Thank you Andrew. I’ve had a ‘start up disk almost full message’ for the last few days, and my laptop is very slow opening things. Yesterday it couldn’t start and showed a flashing question mark instead. I’ve got it started & running now (with help from the installation CD), but that was a great worry and wonder if the lack of space is stuffing up hard disk (=startup disk) somehow.

        I’ve got somewhere between 8 and 45 MB free memory on System Memory in Activity Monitor, fluctuating up and down. I’ve got about 233 MB inactive memory, and the pages out is slowly climbing up, currently about 420 MB. In disk usage I’ve got about 12 GB free and about 99 GB utilised.

        So I wonder if paging out the inactive memory can help, I’ll give iFreeMem a try.

        Ps. I can see that the Chrome browser appears to occupy a massive amount of working memory, does anyone else have that experience?
        It does also frequently crash, which could be because I am in the habit of having too many tabs open at once.

      • Anna says:

        Follow up: I downloaded and ran iFreeMem. It doesn’t make a difference and doesn’t tell me anything that Activity Monitor doesn’t already show. Also, it is just a 15 days trial of a paid product and whenever you start it up you have to select to ‘continue trialling’ – slightly annoying.

        Re. the inactive memory, I found below in another forum:

        “don’t worry about that “inactive” ram, that’s as good as “free”. it means that osx has at some point loaded something in the ram and later on decided that it is no longer needed. of course the ram could be “freed” (completely) but unix systems have made such a decision that the content is kept in the memory in case it is needed in the future. but because that memory is flagged as “inactive”, it can be deleted as soon as some other app needs to have that memory. so it is just one kind of an optimization- .” –
        ( JFreak in http://forums.macrumors.com/showthread.php?t=73631 )

        Makes sense.

  2. Patrick says:

    I was googling around to see what excessive paging was as I was worried my mac was on the high side. After 1 day my Page in/outs are at 1376201/486790. Time for a MacPro since I’m already at the 2GB limit on my CD iMac. *Yikes*

  3. Brent says:

    Well my page ins/outs count is also very high along with having only 18MB of free memory. I had running Finder, Firefox, Microsoft Word, Preview, Safari, and Activity Monitor. I tried closing Word, Preview, and Safari and now it is up to around 180MB free. Now my question is this…lately I’ve been having slow-downs alot and my computer will freeze for a few seconds and I get the beachball. This happens even after a reboot with only Firefox (and sometimes one more program open). Should I get more memory? If so, how do I know what kind to get. I’m a newbie to the MacBook and OSX.


  4. admin says:

    If it is slow straight after a reboot, and there are no page ins, and there is lots of free memory still, then the slow-down is probably not a memory problem, unless you have Leopard, it needs lots of memory, like 2 Gig at least.

  5. stuart says:


    I have also been noticing that my computer lately, slows down alot. Usually, I run Mail, iTunes, Safari, Newsfire, Adium and maybe sometimes transmission. I notice that my page in’s and out’s are quite high. Just yesterday it was the highest that I have ever seen. Today I rebooted and immediately after reboot my page ins were 45,023.

    I am at a loss on what to do. Alot of times my page outs exceed my page ins after a day of running.

    Please help

  6. stuart says:

    Hello again, I just wanted to give an update. I rebooted last night before I went to bed. Again right after start up I has an extreme amount of page in’s. Similar to my above comment. Now less the 16hrs later I now have this
    Swap 2.01GB(3.00GB)
    Page in: 157,558
    Page out: 273,764

    I really am having a hard time grasping what is actually wrong since I have not had this problem until just recently. My warranty is not yet finished for my iMac.

    Please help shed a light on this for me.

    Kind regards,


  7. Drew says:

    @ Stuart,
    If your mac is restarted & not running any apps and you are getting page ins/outs make sure there are no applications running in the background such as iTunes helper, iCal helper menu items dashboard widgets third party apps…
    They should be listed in the activity monitor window.

    It could just be the load that the OS places on your system. You may need more RAM, just keep an eye on the amount of paging and contact Applecare if it concerns you. You don’t say what version of Mac OS or the amount of RAM you have, but more should help. 2 – 4 GB should keep it running smoothly for basic tasks.

    PS the Leopard Activity Monitor specifies the paging in MB/GB units, Im unsure if the units are Kb, MB or GB in your comment.

    Nice article, it helps clarify what is going on with memory.

  8. admin says:

    how much RAM do you have?
    Have you recently upgraded to Leopard?


  9. George says:

    MacBook (Generation 3)
    1GB RAM

    Free: 11.52MB
    Page in: 1218997
    Page Out: 736528

    Page in/Page out are increasing when I went to a website on FireFox.

    Applications in use:

    Microsoft Word
    Activity Monitor

    I also use a lot of Photoshop, iMovie and iPhoto.

    For me, it always seems like FireFox that is creating the whole mess. But I need it because of it’s tools that Safari doesnt have.

    But my main question is obviously, Do I Need More RAM??

  10. sarah says:

    My computer is super slow! My page in/outs are: 74840/25909 and ‘ins’ keep going up. Also the Free is 80 MBs. I just rebooted too? Reboot again? I was just running word and excel and I’m soooo frustrated.

  11. Ben D. says:

    “Free tells you how much free memory you currently have, the higher the better”.

    Actually you should never expect “free” to be high. See this article from Apple for more information: http://support.apple.com/kb/HT1342?viewlocale=en_US

  12. Dunwell says:

    recently, I deleted some file and my ibook G4 wouldnt boot. I rebooted it with “Leopard” (it was Tiger before). now it is so slow I have towait onit to open some firefox pages. It is even doing things I didnt comand it to do.
    I have 512ram 1.33 processor and 60G HD. what can I do?

  13. juelz says:

    I am confused because from your comments it seems as if my system isn’t doing what it is supposed to- my page in is 258.08 and increasing but my page outs is 0 and swap used is 0- is this good or bad? I have 1.04 memory used out of 2 GB but it seems as if an update im trying t o get for my microsoft office is not letting me download because of lack of memory. I am quite confused at this point

    • Athena says:

      Page ins SHOULD increase with every file you open – they occur when data is loaded into RAM.

      Page outs occur when you run out of RAM to be used.

      If your page outs are 0, that’s great! I’d say your download is failing for a reason other than RAM – perhaps hard drive space?

  14. bamakodaker says:

    I wonder if everyone is forgetting something very simple – what about HOW RAM is used? Is your desktop crowded with items using up that RAM? Keep everything IN your harddrive. ONLY have ALIAS’ on your desktop!~ Keep that RAM free.

    • admin says:

      The items on your desktop are still on your harddrive, not in RAM.
      RAM is the memory in your computer where things are loaded when you open them up.

  15. Aayush says:


    I have been noticing that my computer lately, slows down alot. Usually, I run Mail, iTunes, Safari/firefox (though safari makes it more slow), word and excel. I notice that my page in’s and out’s are quite high. Today I rebooted and immediately after reboot my page ins were 36,458.

    I am at a loss on what to do. Alot of times my page outs exceed my page ins after a day of running.

    I have a macbook 2.2Ghz core 2 duo with 1GB RAM and recently upgraded to snow leopard.

    I never faced this problem earlier, although i started having the problem in my leopard only thats why i upgraded to snow leopard.

    Please help

  16. Aayush says:

    will upgrade and try it out…………..thanks………….

  17. Eve says:

    Cheers for that, helped a lot.

  18. Zev says:

    my mac is slow i got 2 gigs of ram mostly use imovie ichat itunes and itenternet and windows,

  19. Nabeel Khan says:

    does anybody know what the conversion is for page ins & outs from Mb’s to just the large numbers you all have showing in your activity monitor?
    Mine shows the amount only in megabytes


  20. HaWook says:

    My Page ins and Page outs are expressed in megabytes (960 and 325, respectively). How can I figure out the actual number?

  21. Roman says:

    Thanks for sharing, guys. Now I’m sure I need to upgrade with no doubts!

  22. charlie says:

    I have a imac osx 10.4.11 (so about 5 years old i think) it has a 2GHz intel core duo and a 1GB 667 MHz.

    When i run the folllowing I have 70MB free and 87660 page in and 43569 page out. Things get slow.


    what im wondering is, is it worth me buying more memory or is my mac reaching the end of its life.i have been told by 2 people that they only have about 5 years in them.
    also if i move my iphoto library(and my lge amount of saved psd documents) onto an external then will this have any effect on the ram or is that totally seperate.
    any advice would be gteat.thankyou!!!

  23. Sanjay says:

    I liked the discussion here. My MAC is also 660 Mhz Intel dual core with 1 GB RAM. It has also gone very slow and I was thinking of upgrading to Snow leopard. It seems that is not the solution. My activity monitor shows just 7 GB free when just 4 programs are running (no video or iTunes) and also the page ins are 276 MB. Is this page on per session or year till date? One observation in activity monitor: pmtool and kernel_task (root) have sent more than a million messages (under messages sent). Anybody has any idea why?

  24. milo says:

    my g4 mac won’t even open the “activity monitor”! the icon pops up but disappears straight away. Doesn’t see the additional internal hard drive either ,not on the desktop. In the system profiler it appears ,but grey!

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

  26. 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

  27. 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.

  28. 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

  29. 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.



  30. 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

  31. 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?

  32. 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.

  33. fluke says:

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

  34. 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?

  35. 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

  36. 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 :)

  37. 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?

  38. 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,

  39. 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?

  40. sarah morgan says:

    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.

  41. 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.

  42. 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?

  43. 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!

  44. 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?

  45. 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!!!!!

  46. 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.

  47. 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.

  48. Luke says:

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

  49. 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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