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. R00bot says:

    Mine is a 4gig RAM macbook pro (year old now) and it says page outs: 6.47 gigabytes.
    Is this bad? What do I do?

  2. Dave says:

    Hey thanks for this article. I had a question and you actually had basically an exact screenshot of my system! More RAM it is!

    • Rob says:

      Me too, almost an exact screen grab from my Mac! – I thought it might of been some sort of scam at first as it was uncanny :-)

      Thanks for the article, been very helpful and I’ll use your link when I order my memory after Christmas!

  3. C Winkler says:

    I’m so glad I found your Mac site! Thank you, Brother! Your post helped me so much! I’ll be a frequent visitor from now on. God bless you!

  4. Thank you! EXCELLENT explanation of what to look for and what it means. I need a memory upgrade…going to your affiliate link now!

  5. kate says:

    I am not good at computers. Went through your tutorial and it says I have 587 MB of free space. My page outs are 100.00 KB. The graph shows a decent hunk of green and at the bottom it says 2 GB. Is more memory needed? The other day I tried to open excel and it said it couldn’t open it because I didn’t have enough memory so that seems to suggest I do, but yet going through your exercise made me think I had enough. Help!

  6. Chrish says:

    I’ve just upgraded my iMac from 4GB to 12GB of memory. Do I now need to do anything to optimize it at all, or is it OK to just leave as is?

  7. Tim says:

    Haha I was wondering why my mac was so slow. I got my 17″ pro for a year and a half now and was really unpleased that the performance was so bad already.
    Turns out that I got 30GB page outs at the moment. Thanks for this article, I immediately ordered in 16G in stead of the 4GB I use now.

  8. JoJoHants says:

    Hi, used this help the other day which really did highlight a lot of page outs, so installed Grand Perspective to clean out some old stuff and used an app to tidy up loads of duplicate files (result form shifting over from a windows pc about 18 months ago).

    So went back into my Utilities folder today to see if it had helped and did I still need to get an external hard drive, but the thing doesn’t look the say any more??

    There is no graph, no tab at the bottom?? There are tabs at the top identified as CPU / Memory / Energy / Disk / Network

    So I assumed they had just removed the word ‘system’ from the memory tab.
    The info looks pretty similar, but in a different format, but there is no FREE info & no PAGEIN/OUTS info.

    Can anyone help please??? I dont want to buy something I may not need, but would like to understand this new format. Wish I could add a screen print for you.

    Thanks from one un-technical female!

  9. Geertje says:

    Thanks! Been searching for info to be able to decide whether I could safely install Maverick. I definitely need more memory, and gonna check if my mac can handle more RAM (my mac gets overheated pretty quick), before I even start to think of upgrading to Maverick.

    I own a mac book 10.6.8, from 2006,
    processor: 2GHz core 2 Duo,
    memory: 2 GB 667 MHz DDR2 SDRAM

    System memory
    – free ca 23 MB
    – page outs: 65,6 MB to 93 MB

    Gonna check my activity monitor more often from now on, to see which (useless) programs/plugins are open / taking away too much memory space.

  10. Stephan Keen says:

    A nice detailed article on whether you need a Mac RAM upgrade. Thanks for sharing. I would also advice that you carry out a SMC (system controller reset) and PRAM reset to see if your Mac will speed up, before splurging on memory that can be quite expensive these days.

  11. Stephan Keen says:

    Oh, by the way, for anyone interested in instructions on how to carry out a SMC and PRAM reset, here are good instructions. http://machmachines.com/macbook-pro-running-slow-heres-how-to-fix-it/

  12. Ranz says:

    MacBook Pro Mid 2012 (4GB RAM)

    Free: 299.4 MB
    Wired: 1.11 GB
    Active:1.08 GB
    Inactive: 1.53 GB
    Used: 3.71GB
    VM size: 215 GB
    Page ins: 5.92 GB
    Page outs: 7.46 GB
    Swap used: 2.54 GB

    Illustrator and Photoshop are stalling on me so I know I need more RAM esp as I typically use large files in PS… but you guys think I should get 8GB or 16GB?? O.o

  13. Bob C says:

    I have bought memory from Crucial a number of times. Sotftware on its website helps you to identify which RAM module will fit your Mac and the speed of delivery of the product is excellent. I’m not affiliated to the company and I would use no other.

  14. Darren says:

    Just tried your link to crucial so you get your commission but I got a 404 error page not found. Just thought you should know. If you email me back with an updated link I can hold off on the purchase until then.


  15. Joliepop says:

    I am dumb as dirt and I was able to read and understand this article. Your screen captures were great! I was able to match w/my Activity Monitor and I still might bring my Mac to the Genius Bar but at least I am more informed that I need RAM. Thanks so much!!!

  16. Geno says:

    Great article, but I have a MacBook Pro5.5 (late 2009), running Mavericks, and the Activity Monitor doesn’t have tabs at the bottom. I’m not seeing anything about Free and Page Outs, so I wonder if something changed with Mavericks? How can I ascertain that same information? It does show Physical Memory (4GB) and Memory Used (about all of it), but I’d like to ensure upgrading my memory is going to have a positive impact on my system performance, which has become progressively worse.

    • Ally says:

      I have the same issue as Geno and JoJoHants with the difference layout – does anyone have any information about how we can get the one with the charts and the mention of Free and Page Outs?

    • Michelle says:

      Did you ever get an update on this? I have macbook late 2009 as well and not seeing the page in or out info.

  17. Brenda says:

    Tks, : ) love this site so easy to get an answer & understand. Dont leave here thinking did that help me or not. Graphs really break it down 2 simple. Marking this site FOR SURE (I’ll B BACK)

  18. Phil says:

    Hi my memory slot says ” PHYSICAL MEMORY 4.00 GB

    Now I’m confused, though my computer does say’ system overload’ in new Garageband 10.3.

    Any help appreciated very much, thanks a lot :)

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