Apple Memory For I Mac

“No matter what I do, my Mac is still slow”, an average tech-consultant hears this phrase multiple times a day. Give a person even the most powerful computer, and pretty soon it will be cluttered with apps, extensions, and things that are too much for it to handle. To reverse it, one has to go back and сlean up the mess, removing memory agents one by one. Prepare for a fight — every byte of memory is at stake. So let’s put your Mac on a diet and get it more free RAM to breathe freely.

First, remove desktop clutter. Get a combination of Setapp apps that clear away unneeded desktop files.

Take the guesswork out of upgrading your Mac with Crucial ® memory for Mac systems. Since Apple ® computers often have very specific memory requirements, including particular component densities, speeds, and SPD programming specifications, it’s important to use memory that’s engineered for your Mac. With more than a decade of experience manufacturing and developing memory. Carry-in repair: Take your Mac to an Apple Store or other Apple Authorized Service Provider; Hardware coverage for your Mac computer, battery, included accessories such as the power adapter, Apple memory (RAM), Airport and Apple USB SuperDrive; AppleCare products must be purchased with an applicable Apple device.

Download Declutter Free

“Your system has run out of application memory”

How do you know your Mac is low on memory? Floating “rainbow wheels” aside, you may notice your Mac now takes ages to load. You’ll also see many browser applications crashing. You’ll be also thrown warning messages as “Your system has run out of application memory”. To help it, you should first visit the Activity monitor to see memory usage on Mac.

How to check RAM usage on Mac

Go to Applications and type in Activity Monitor in the search bar. This invokes a good old Activity Monitor that should tell how much free memory you’ve got left.

A shortcut to open Activity Monitor:

Press F4 and start typing Activity Monitor in the search bar. Finder mac os x show hidden files.

I’ve attached a screenshot from my Mac and as you can see my memory usage almost reached full capacity. Here’s what it all means:

App memory: taken by apps and processes
Wired memory: reserved by apps, can’t be freed up
Compressed: inactive, can be used by other apps
Swap used: memory used by macOS
Cached files: memory you can really use

Memory For Imac

Notice the colored graph under Memory Pressure. If your graph is all but red and yellow, your Mac is really gasping for fresh memory. It seems counter-intuitive, but “available memory” your Activity Monitor is not that important after all. In fact, it’s a system intended behavior to use all memory resources when available. On the contrary, the Memory Pressure graph is much more telling, so grow a habit to check this graph in the Activity Monitor every now and then.

How to check CPU usage on Mac

Open the CPU tab in Activity Monitor to keep in check CPU-heavy processes. Normally an app would be using 0-4% of CPU. If it takes abnormally more than that, go inside that particular item in the list and press the Quit button.

How to free up memory on Mac

Tip # 1. Remove Login Items to lower Mac memory usage

Login items are programs that load automatically upon Mac startup. Some of them covertly add themselves to the list and this is no good. If you’re looking to free up RAM, they are the first candidates for deletion. Don’t worry, you’re not deleting the app itself, you just stop it from auto-launching every time.

So, to remove Login Items and at the same time reduce your memory usage of your Mac, you need to:

  1. Open System Preferences and select Users & Groups.
  2. Click your nickname on the left.
  3. Select the Login Items tab.
  4. Check programs you don’t want to load as your Mac starts.
  5. Press the “–” sign below.

Now, you won’t see these apps pop up the moment you turn on your Mac. Although this method doesn’t require some superpowers of yours, some special Mac optimization and memory cleaner tools may do the job faster and ensure the smooth performance of your Mac. CleanMyMac X is an excellent example of such software. Here’s how to disable Login Items with CleanMyMac X:

  1. Download it for free and go to the Optimization tab.
  2. Check Login Items to see the list of apps that get opened when you start your Mac.
  3. Click Remove.

As you’ve already come to the Optimization module of CleanMyMac, you can also fix hung apps and heavy memory consumers there. In this way, you’ll free up the solid amount of RAM on Mac — 100% free of charge.

Tip # 2. Free up disk space if Mac is low on memory

The available space on your Mac’s drive translates into virtual memory. This comes to save you when you’ve run out of physical RAM. So now your computer relies on your hard drive space to keep your apps going.

The classic geek rule of thumb holds it that you should keep at least 20% of disk space on your startup drive. Not only this potentially reduces your future spending on iCloud storage but it also keeps your Mac speedier.

What to delete to free up space:

  • Large unused files, like movies
  • Old downloads
  • Rarely used applications
  • System junk

But here’s a simpler solution to save your time — clean up your drive with CleanMyMac X— the app I’ve mentioned above. Many users recommend it as an excellent way to free up more space because it searches for large & old files, useless system files, Photo junk, mail attachments and shows everything you can safely delete. Interestingly, it finds about 74 GB of junk on an average computer.

Extra trick: How to free up RAM on Mac with CleanMyMac X

If you have downloaded CleanMyMac, you may also take advantage of its amazing feature — the ability to free up RAM in a few seconds. Try this next time you see “Your system has run out of application memory” message.

  1. Go to the Maintenance tab on the left.
  2. Click Free Up RAM.
  3. Click Run.

As simple as that!

And you can do it even if you download a free version of the app.

Tip # 3. Clean up your Desktop

This tip always comes at the bottom of instructions and unfairly so as it is quite effective. Without even looking at your Desktop I would assume it’s cluttered with mountains of icons. Thing is, your macOS was designed in a way that it treats every Desktop icon as a little active window. The more icons, the heavier memory usage on Mac. So in order to release available memory resources, it’s recommended to keep your Desktop clean.

You don’t have to do it all by yourself. With apps like Declutter and Spotless, every desktop cleaning session will be scheduled in advance and executed automatically. Your only job is to define the rules on how your files should be organized.

Tip #4. Clear cache files

Another way to free up RAM on Mac is to clear it of cache files. Of course, it won’t save you gigabytes of space, but deleting cache regularly, you can help your Mac run faster and avoid system issues.

So, to remove cache files on your Mac, you need to:

  1. Open Finder.
  2. From the Go menu, select Go to Folder.
  3. Type ~/Library/Caches in the field and press Go.
  4. In the window that appears, you will see all your cache files.
  5. Press Command+A to select all files or delete files one by one.
  6. Enter your user name and password to confirm.

If you find some files still in the folder after you emptied it, maybe you have some windows open on your Mac. Just like that, you can save up some space on your Mac. Don’t forget to empty the bin afterward.

Tip # 5. Tune up Chrome’s Task Manager

Although Google Chrome is not the one to blame for massive memory usage, it can indeed affect your Mac's performance. If you use Chrome as your primary browser, you probably have many windows opened there. Chrome runs a lot of processes to ensure a fast browsing experience for you. So, it uses your RAM for storing your tabs, plugins, and extensions. Look at how many entries Google Chrome has in Activity Monitor:

The question then arises, 'Why does Chrome use so much RAM?' The thing is that each process is responsible for a separate plugin or extension of your browser. For example, when a tab unexpectedly falls, you need to refresh it to continue your work there. If one process were responsible for all tabs and extensions, you would need to restart the whole browser instead. Can you imagine how many times would you do that? That’s the proper answer to why Chrome uses so much RAM.

I’ve been using Chrome for some years only to discover (recently) that Chrome had a task manager of its own. You can use it to force quit memory-heavy processes in the browser. It’s a handy tool because it lets you see how a page weighs on CPU usage on a Mac.

  1. Go to Chrome settings (dotted icon in the top right corner)
  2. Click More tools -> Task Manager

To free up even more RAM, close the GPU process. The GPU Process, though helpful in theory to accelerate pages, eats up a considerable amount of memory. Click to end it to free up RAM on your Mac.

Tip # 6. Manage RAM usage with CleanMyMac X menu

CleanMyMac X has another useful and convenient feature for managing your Mac’s performance and memory usage. As you install CleanMyMac X and start it for the first time, it’s icon will appear in your menu bar. Click the icon to open the CleanMyMac X menu. Here you can find updates on the current condition of your Mac and perform quick tweaks to increase your Mac's speed. Whenever you feel like your Mac underperforms, open the CleanMyMac X menu to check how much RAM is available and free it up as well.

Tip # 7. Close Finder windows

Okay, suppose you’re still asking yourself, how do I clear RAM on my MacBook Pro/MacBook Air. The next trick is as magical (you’ll see for yourself) as it is time-saving. It’s no secret that each window in the Finder eats up RAM. But how many open windows are there? Some of them are collapsed or stacked in some blind spot on your screen. This Finder command merges all your windows into one. See how to do it:

Click on Finder > Window > Merge All Windows

Now you can manage Finder windows more effectively and free up memory on MacBook.

What else you can do to minimize memory usage on Mac

I’ve saved the easiest tips for the end, as long as these ones are self-explanatory.

  • Replace AdBlock (very memory-demanding) with a lighter extension
  • Keep fewer opened tabs in the browser
  • Restart your Mac more often to free up RAM
  • Close all hung-up print queues

That was my take on how to make your Mac a bit speedier to use. If you’re looking for more guidance, check simple ways to speed up your Mac.

Frequently Asked Questions

How to check application memory on Mac?

To check RAM usage on your Mac, go to Activity Monitor (Applications > Utilities). In the Memory tab, you will see all the active processes that are using your Mac’s RAM. At the end of the window, there is a Memory Used graph, which indicates how much application memory is used.

How to find out whether your Mac needs more RAM?

Your Mac may be using almost all its RAM, but you don’t need more if it’s using it efficiently. Open Activity Monitor and go to the Memory tab. The Memory Pressure graph shows the current condition of your RAM: green color means your Mac’s using RAM effectively, while yellow is a sign that some application or process is using too much of application memory. The red memory pressure signals that your Mac needs more RAM.

How to quickly free up RAM on your MacBook?

To free up RAM on your Mac, firstly, you should find out what app uses so much of your memory. The memory-heavy programs are listed in Activity Monitor, Memory tab. If there is an app you aren’t using at the moment, click it and press the “X” sign to quit it. This will, in turn, free some of the application memory

These might also interest you:

Choose your iMac model

If you're not sure which iMac you have, you can identify your iMac and then select it from the list below.

27-inch

24-inch

21.5-inch

  • iMac (Retina 4K, 21.5-inch, 2019)*
  • iMac (Retina 4K, 21.5-inch, 2017)*
  • iMac (21.5-inch, 2017)*
  • iMac (21.5 inch, Mid 2014)*
  • iMac (21.5-inch, Late 2013)*
  • iMac (21.5-inch, Late 2012)*

20-inch

17-inch

* Memory is not removable by users on iMac (21.5-inch, Late 2012), iMac (21.5-inch, Late 2013), iMac (21.5-inch, Mid 2014), iMac (21.5-inch, 2017), iMac (Retina 4K, 21.5-inch, 2017) and iMac (Retina 4K, 21.5-inch, 2019). If the memory in one of these computers needs repair service, contact an Apple Retail Store or Apple Authorised Service Provider. If you’d like to upgrade the memory in one of these models, an Apple Authorised Service Provider can help. Before you schedule an appointment, confirm that the specific Apple Authorised Service Provider offers memory upgrade services.

Memory in iMac (21.5-inch, Late 2015) and iMac (Retina 4K, 21.5-inch, Late 2015) is not upgradeable.

iMac (Retina 5K, 27-inch, 2020)

Get memory specifications for iMac (Retina 5K, 27-inch, 2020), then learn how to install memory in this model.

Memory specifications

This iMac model features Synchronous Dynamic Random-Access Memory (SDRAM) slots on the rear of the computer near the vents with these memory specifications:

Number of memory slots4
Base memory8 GB (2 x 4 GB DIMMs)
Maximum memory128 GB (4 x 32 GB DIMMs)

For optimal memory performance, DIMMs should be the same capacity, speed and supplier. Use Small Outline Dual Inline Memory Modules (SO-DIMM) that meet all of these criteria:

  • PC4-21333
  • Unbuffered
  • Nonparity
  • 260-pin
  • 2666MHz DDR4 SDRAM

If you have mixed capacity DIMMs, see the install memory section for installation recommendations.

iMac (Retina 5K, 27-inch, 2019)

Get memory specifications for iMac (Retina 5K, 27-inch, 2019), then learn how to install memory in this model.

Memory specifications

This iMac model features Synchronous Dynamic Random-Access Memory (SDRAM) slots on the rear of the computer near the vents with these memory specifications:

Number of memory slots4
Base memory8 GB (2 x 4 GB DIMMs)
Maximum memory64 GB (4 x 16 GB DIMMs)
Apple memory macbook pro

Use Small Outline Dual Inline Memory Modules (SO-DIMM) that meet all of these criteria:

  • PC4-21333
  • Unbuffered
  • Nonparity
  • 260-pin
  • 2666MHz DDR4 SDRAM

iMac (Retina 5K, 27-inch, 2017)

Get memory specifications for iMac (Retina 5K, 27-inch, 2017), then learn how to install memory in this model.

Memory specifications

This iMac model features Synchronous Dynamic Random-Access Memory (SDRAM) slots on the rear of the computer near the vents with these memory specifications:

Number of memory slots4
Base memory8 GB (2 x 4 GB DIMMs)
Maximum memory64 GB (4 x 16 GB DIMMs)

Use Small Outline Dual Inline Memory Modules (SO-DIMM) that meet all of these criteria:

  • PC4-2400 (19200)
  • Unbuffered
  • Nonparity
  • 260-pin
  • 2400MHz DDR4 SDRAM

iMac (Retina 5K, 27-inch, Late 2015)

Get memory specifications for iMac (Retina 5K, 27-inch, Late 2015), then learn how to install memory in this model.

Memory specifications

This iMac model features Synchronous Dynamic Random-Access Memory (SDRAM) slots on the rear of the computer near the vents with these memory specifications:

Number of memory slots4
Base memory8 GB
Maximum memory32GB

Use Small Outline Dual Inline Memory Modules (SO-DIMM) that meet all of these criteria:

  • PC3-14900
  • Unbuffered
  • Nonparity
  • 204-pin
  • 1867MHz DDR3 SDRAM

For these 27-inch models

Get memory specifications for the following iMac models, then learn how to install memory in them:

  • iMac (Retina 5K, 27-inch, Mid 2015)
  • iMac (Retina 5K, 27-inch, Late 2014)
  • iMac (27-inch, Late 2013)
  • iMac (27-inch, Late 2012)

Memory specifications

These iMac models feature Synchronous Dynamic Random-Access Memory (SDRAM) slots on the rear of the computer near the vents with these memory specifications:

Number of memory slots4
Base memory8 GB
Maximum memory32GB

Use Small Outline Dual Inline Memory Modules (SO-DIMM) that meet all of these criteria:

  • PC3-12800
  • Unbuffered
  • Nonparity
  • 204-pin
  • 1600MHz DDR3 SDRAM

Installing memory

The internal components of your iMac can be warm. If you've been using your iMac, wait ten minutes after shutting it down to let the internal components cool.

After you've shut down your iMac and given it some time to cool down, follow these steps:

  1. Disconnect the power cord and all other cables from your computer.
  2. Place a soft, clean towel or cloth on the desk or other flat surface to prevent scratching the display.
  3. Hold the sides of the computer and slowly lay the computer face-down on the towel or cloth.
  4. Open the memory compartment door by pressing the small grey button located just above the AC power port:
  5. The memory compartment door will open as the button is pushed in. Remove the compartment door and set it aside:
  6. A diagram on the underside of the compartment door shows the memory cage levers and the orientation of the DIMM. Locate the two levers on the right and left sides of the memory cage. Push the two levers outwards to release the memory cage:
  7. After the memory cage has been released, pull the memory cage levers towards you, allowing access to each DIMM slot.
  8. Remove a DIMM by pulling the module straight up and out. Note the location of the notch on the bottom of the DIMM. When reinstalling DIMMs, the notch must be orientated correctly or the DIMM won't fully insert:
  9. Replace or install a DIMM by setting it down into the slot and pressing firmly until you feel the DIMM click into the slot. When you insert a DIMM, make sure you align the notch on the DIMM to the DIMM slot. Find your model below for specific installation instructions and notch locations:
    • iMac (Retina 5K, 27-inch, 2020) DIMMs have a notch on the bottom, slightly to the left of the centre. If your DIMMs are mixed in capacity, minimise the capacity difference between Channel A (slots 1 and 2) and Channel B (slots 3 and 4) when possible.
    • iMac (Retina 5K, 27-inch, 2019) DIMMs have a notch on the bottom, slightly to the left of the centre:
    • iMac (27-inch, Late 2012) and iMac (Retina 5K, 27-inch, 2017) DIMMs have a notch on the bottom left:
    • iMac (27-inch, Late 2013) and iMac (Retina 5K, 27-inch, Late 2014, Mid 2015, and Late 2015) DIMMs have a notch on the bottom right:
  10. After you've installed all of your DIMMs, push both memory cage levers back into the housing until they've locked into place:
  11. Replace the memory compartment door. You don't need to press the compartment door release button when replacing the compartment door.
  12. Place the computer in its upright position. Reconnect the power cord and all other cables to the computer, then start up the computer.

Your iMac performs a memory initialisation procedure when you first turn it on after upgrading memory or rearranging DIMMs. This process can take 30 seconds or more, and the display of your iMac remains dark until it's finished. Make sure you let the memory initialisation complete.

For these 27-inch and 21.5-inch models

Get memory specifications for the following iMac models, then learn how to install memory in them:

Apple Memory For Imac

  • iMac (27-inch, Mid 2011)
  • iMac (21.5-inch, Mid 2011)
  • iMac (27-inch, Mid 2010)
  • iMac (21.5-inch, Mid 2010)
  • iMac (27-inch, Late 2009)
  • iMac (21.5-inch, Late 2009)

Memory specifications

Number of memory slots4
Base memory4 GB (but is configured to order)
Maximum memory16GB
For iMac (Late 2009), you can use 2 GB or 4 GB RAM SO-DIMMs of 1066MHz DDR3 SDRAM in each slot. For iMac (Mid 2010) and iMac (Mid 2011), use 2 GB or 4 GB RAM SO-DIMMs of 1333MHz DDR3 SDRAM in each slot.

Use Small Outline Dual Inline Memory Modules (SO-DIMM) that meet all of these criteria:

iMac (Mid 2011)iMac (Mid 2010)iMac (Late 2009)
PC3-10600PC3-10600PC3-8500
UnbufferedUnbufferedUnbuffered
NonparityNonparityNonparity
204-pin204-pin204-pin
1333MHz DDR3 SDRAM1333MHz DDR3 SDRAM1066MHz DDR3 SDRAM

i5 and i7 Quad Core iMac computers come with both top memory slots populated. These computers will not start up if only a single DIMM is installed in any bottom slot; these computers should operate normally with a single DIMM installed in any top slot.

Core Duo iMac computers should operate normally with a single DIMM installed in any slot, top or bottom. ('Top' and 'bottom' slots refer to the orientation of the slots in the pictures below. 'Top' refers to the slots closest to the display; 'bottom' refers to the slots closest to the stand.)

Installing memory

The internal components of your iMac can be warm. If you've been using your iMac, wait ten minutes after shutting it down to let the internal components cool.

After you've shut down your iMac and given it some time to cool down, follow these steps:

  1. Disconnect the power cord and all other cables from your computer.
  2. Place a soft, clean towel or cloth on the desk or other flat surface to prevent scratching the display.
  3. Hold the sides of the computer and slowly lay the computer face-down on the towel or cloth.
  4. Using a Philips screwdriver, remove the RAM access door in the bottom of your computer:
  5. Remove the access door and set it aside.
  6. Untuck the tab in the memory compartment. If you're replacing a memory module, gently pull the tab to eject any installed memory module:
  7. Insert your new or replacement SO-DIMM into the empty slot, noting the orientation of the keyway of the SO-DIMM as shown below.
  8. After you've inserted it, press the DIMM up into the slot. There should be a slight click when you seat the memory correctly:
  9. Tuck the tabs above the memory DIMMs, and reinstall the memory access door:
  10. Place the computer in its upright position. Reconnect the power cord and all other cables to the computer, then start up the computer.

For these 24-inch and 20-inch models

Get memory specifications for the following iMac models, then learn how to install memory in them:

  • iMac (24-inch, Early 2009)
  • iMac (20-inch, Early 2009)
  • iMac (24-inch, Early 2008)
  • iMac (20-inch, Early 2008)
  • iMac (24-inch Mid 2007)
  • iMac (20-inch, Mid 2007)

Memory specifications

These iMac computers have two side-by-side Synchronous Dynamic Random-Access Memory (SDRAM) slots in the bottom of the computer.

The maximum amount of random-access memory (RAM) you can install in each computer is:

ComputerMemory TypeMaximum Memory
iMac (Mid 2007)DDR24 GB (2 x 2 GB)
iMac (Early 2008)DDR24 GB (2 x 2 GB)
iMac (Early 2009)DDR38 GB (2 x 4 GB)

You can use a 1 GB or 2 GB RAM module in each slot for iMac (Mid 2007) and iMac (Early 2008). Use 1 GB, 2 GB or 4 GB modules in each slot for the iMac (Early 2009).

Use Small Outline Dual Inline Memory Modules (SO-DIMM) that meet all of these criteria:

iMac (Mid 2007)iMac (Early 2008)iMac (Early 2009)
PC2-5300PC2-6400PC3-8500
UnbufferedUnbufferedUnbuffered
NonparityNonparityNonparity
200-pin200-pin204-pin
667MHz DDR2 SDRAM800MHz DDR2 SDRAM1066MHz DDR3 SDRAM

DIMMs with any of the following features aren't supported:

  • Registers or buffers
  • PLLs
  • Error-correcting code (ECC)
  • Parity
  • Extended data out (EDO) RAM

Installing memory

The internal components of your iMac can be warm. If you've been using your iMac, wait ten minutes after shutting it down to let the internal components cool.

After your iMac has cooled down, follow these steps:

  1. Disconnect the power cord and all other cables from your computer.
  2. Place a soft, clean towel or cloth on the desk or other flat surface to prevent scratching the display.
  3. Hold the sides of the computer and slowly lay the computer face-down on the towel or cloth.
  4. Using a Philips screwdriver, remove the RAM access door in the bottom of the computer:
  5. Remove the access door and set it aside.
  6. Untuck the tab in the memory compartment. If you're replacing a memory module, untuck the tab and pull it to eject any installed memory module:
  7. Insert your new or replacement RAM SO-DIMM into the empty slot, noting the orientation of the keyway of the SO-DIMM as shown above.
  8. After you've inserted it, press the DIMM up into the slot. There should be a slight click when you seat the memory correctly.
  9. Tuck the tabs above the memory DIMMs, and reinstall the memory access door:
  10. Place the computer in its upright position. Reconnect the power cord and all other cables to the computer, then start up the computer.

For these 20-inch and 17-inch models

Get memory specifications for the following iMac models, then learn how to install memory in them:

  • iMac (20-inch Late 2006)
  • iMac (17-inch, Late 2006 CD)
  • iMac (17-inch, Late 2006)
  • iMac (17-inch, Mid 2006)
  • iMac (20-inch, Early 2006)
  • iMac (17-inch, Early 2006)

Memory specifications

Number of memory slots2
Base memory1 GBTwo 512 MB DIMMs; one in each of the memory slotsiMac (Late 2006)
512 MBOne DDR2 SDRAM installed into the top slotiMac (17-inch Late 2006 CD)
512 MBTwo 256 MB DIMMs; one in each of the memory slotsiMac (Mid 2006)
512 MBOne DDR2 SDRAM installed into the top slotiMac (Early 2006)
Maximum memory4 GB2 GB SO-DIMM in each of the two slots*iMac (Late 2006)
2 GB1 GB SO-DIMM in each of the two slotsiMac (17-inch Late 2006 CD)
iMac (Early 2006)
Memory card specificationsCompatible:
- Small Outline Dual Inline Memory Module (DDR SO-DIMM) format
- PC2-5300
- Nonparity
- 200-pin
- 667 MHz
- DDR3 SDRAM
Not compatible:
- Registers or buffers
- PLLs
- ECC
- Parity
- EDO RAM

For best performance, fill both memory slots, installing an equal memory module in each slot.
*iMac (Late 2006) uses a maximum of 3GB of RAM.

Installing memory in the bottom slot

The internal components of your iMac can be warm. If you've been using your iMac, wait ten minutes after shutting it down to let the internal components cool.

After you've shut down your iMac and given it some time to cool down, follow these steps:

  1. Disconnect the power cord and all other cables from your computer.
  2. Place a soft, clean towel or cloth on the desk or other flat surface to prevent scratching the display.
  3. Hold the sides of the computer and slowly lay the computer face-down on the towel or cloth.
  4. Using a Phillips screwdriver, remove the RAM access door on the bottom of the iMac and set it aside:
  5. Move the DIMM ejector clips to their fully open position:
  6. Insert your RAM SO-DIMM into the bottom slot, keeping in mind the orientation of the keyed SO-DIMM:
  7. After you've inserted it, press the DIMM up into the slot with your thumbs. Don't use the DIMM ejector clips to push in the DIMM, as this may damage the SDRAM DIMM.There should be a slight click when you seat the memory fully.
  8. Close the ejector clips:
  9. Reinstall the memory access door:
  10. Place the computer in its upright position. Reconnect the power cord and all other cables to the computer, then start up the computer.

Replacing memory in the top slot

After you've shut down your iMac and given it some time to cool down, follow these steps:

  1. Disconnect the power cord and all other cables from your computer.
  2. Place a soft, clean towel or cloth on the desk or other flat surface to prevent scratching the display.
  3. Hold the sides of the computer and slowly lay the computer face-down on the towel or cloth.
  4. Using a Phillips screwdriver, remove the RAM access door on the bottom of the iMac and set it aside:
  5. Pull the two levers on each side of the memory compartment to eject the memory module that's already installed:
  6. Remove the memory module from your iMac as shown below:
  7. Insert your RAM SO-DIMM into the top slot, noting the orientation of the keyed SO-DIMM:
  8. After you've inserted it, press the DIMM up into the slot with your thumbs. Don't use the DIMM ejector clips to push in the DIMM, as this may damage the SDRAM DIMM.There should be a slight click when you seat the memory fully.
  9. Close the ejector clips:
  10. Reinstall the memory access door:
  11. Place the computer in its upright position. Reconnect the power cord and all other cables to the computer, then start up the computer.

If your iMac makes a tone after you install memory

iMac models introduced before 2017 might make a warning sound when you start up after installing or replacing memory:

  • One tone, repeating every five seconds signals that no RAM is installed.
  • Three successive tones, then a five-second pause (repeating) signals that RAM doesn't pass a data integrity check.

If you hear these tones, confirm that the memory you installed is compatible with your iMac and that it's installed correctly by reseating the memory. If your Mac continues to make the tone, contact Apple Support.

Confirm that your iMac recognises its new memory

After you've installed memory, you should confirm that your iMac recognises the new RAM by choosing Apple () menu > About This Mac.

The window that appears lists the total memory, including the amount of memory that originally came with the computer plus the newly added memory. If all the memory in the iMac has been replaced, it lists the new total of all installed RAM.

For detailed information about the memory installed in your iMac, click System Report. Then choose Memory under the Hardware section in the left side of System Information.

If your computer doesn't recognise the memory or doesn't start up correctly, confirm that the RAM you installed is compatible with your iMac and that it's installed correctly by reseating the memory. If you continue to have issues with the memory in your iMac, contact Apple Support.