Install memory in an iMac

Learn how to install or replace memory in your iMac computer.

Choose your iMac model

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

17-inch

20-inch

21.5-inch

24-inch

27-inch

*Note:

• Memory is not removable by users on iMac (21.5-inch, Late 2012), iMac (21.5-inch, Late 2013), and iMac (21.5-inch, Mid 2014). If the memory in one of these computers needs to be replaced, contact an Apple Retail Store or Apple Authorized Service Provider. If you’d like to upgrade the memory in one of these models, an Apple Authorized Service Provider can help.

• Memory in iMac (21-inch, Late 2015) and iMac (Retina 4K, 21-inch, Late 2015) is not upgradeable.

For this 27-inch model

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

Memory specifications

This iMac model feature Synchronous Dynamic Random-Access Memory (SDRAM) slots near the bottom of the computer with these memory specifications:

Number of memory slots 4
Base memory 8 GB
Maximum memory 32 GB

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

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

Learn how to remove or install memory in this iMac model.

For these 27-inch models

  • 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 near the bottom of the computer with these memory specifications:

Number of memory slots 4
Base memory 8 GB
Maximum memory 32 GB

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

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

Learn how to remove or install memory in these iMac models.

Removing or installing memory

Warning: 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, then continue with these instructions:

  1. Turn off your computer by choosing Shut Down from the Apple menu.
  2. Disconnect the power cord and all other cables from your computer.
  3. Place a soft, clean towel or cloth on the desk or other flat surface to prevent scratching the display.
  4. Hold the sides of the computer and slowly lay the computer face-down on the towel or cloth.
  5. Open the memory compartment door by pressing the small grey button located just above the AC power port.  

  6. The memory compartment door will open as the button is pushed in. Remove the compartment door and set it aside.  

    A diagram on the underside of the compartment door shows the memory cage levers and the orientation of the DIMM.
  7. Locate two levers on the right and left sides of the memory cage. Push the two memory cage levers outward to release the memory cage.  

  8. Once the memory cage is released, pull the memory cage levers toward you, allowing access to each DIMM slot.
  9. 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 oriented correctly or the DIMM won't fully insert.

  10. Replace or install a DIMM by setting it down into the slot and pressing firmly until you feel the DIMM click into the slot. 
    The DIMM slot shown below is for the the iMac (27-inch, Late 2013) and iMac (Retina 5K, 27-inch, Late 2014, Mid 2015, and Late 2015). It requires that you insert the DIMM with the notch on the bottom oriented towards the right:

    The iMac (27-inch, Late 2012) has the notch on the bottom left, as shown below:
  11. Once you have all of your DIMMs installed, push the memory cage levers back into the housing until they subtly click back into place.
  12. Replace the memory compartment door. You don't need to depress the compartment door release button when replacing the compartment door.
  13. 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 27-inch and 21.5-inch models

  • 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

These iMac models have these memory specifications:

Number of memory slots 4
Base memory 4 GB (but is configured to order)
Maximum memory 16 GB
For the iMac (Late 2009) models, you can use 2 GB or 4 GB RAM SO-DIMMs of 1066 MHz DDR3 SDRAM in each slot. For the iMac (Mid 2010) and iMac (Mid 2011) models, use 2 GB or 4 GB RAM SO-DIMMs of 1333 MHz 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)
PC3-10600 PC3-10600 PC3-8500
Unbuffered Unbuffered Unbuffered
Nonparity Nonparity Nonparity
204-pin 204-pin 204-pin
1333MHz DDR3 SDRAM 1333MHz DDR3 SDRAM 1066MHz 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.)

 

Removing or installing memory

Warning: 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, then continue with these instructions:

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

For these 24-inch and 20-inch models

  • 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 the computer is:

Computer Memory Type Maximum Memory
iMac (Mid 2007) DDR2 4GB (2x2GB)
iMac (Early 2008) DDR2 4GB (2x2GB)
iMac (Early 2009) DDR3 8GB (2x4GB)

You can use a 1GB or 2 GB RAM module in each slot for iMac (Mid 2007) and iMac (Early 2008). Use 1GB, 2GB, or 4GB 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)
PC2-5300 PC2-6400 PC3-8500
Unbuffered Unbuffered Unbuffered
Nonparity Nonparity Nonparity
200-pin 200-pin 204-pin
667MHz DDR2 SDRAM 800MHz DDR2 SDRAM 1066MHz 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

Removing or installing memory

Warning: 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, then continue with these instructions:

  1. Turn off your computer by choosing Shut Down from the Apple menu.
  2. Disconnect the power cord and all other cables from your computer.
  3. Place a soft, clean towel or cloth on the desk or other flat surface to prevent scratching the display.
  4. Hold the sides of the computer and slowly lay the computer face-down on the towel or cloth.
  5. Using a Philips screwdriver, remove the RAM access door in the bottom of the computer.
  6. Remove the access door and set it aside.
  7. Untuck the tab in the memory compartment. If you are replacing a memory module, untuck the tab and pull it to eject any installed memory module.
  8. 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.
  9. After you insert it, press the DIMM up into the slot. There should be a slight click when you seat the memory correctly.
  10. Tuck the tabs above the memory DIMMs, and 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.

For these 20-inch and 17-inch models

  • 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 slots 2
Base memory 1 GB Two 512 MB DIMMs; one in each of the memory slots iMac (Late 2006)
512 MB One DDR2 SDRAM installed into the top slot iMac (17-inch Late 2006 CD)
512 MB Two 256 MB DIMMs; one in each of the memory slots iMac (Mid 2006)
512 MB One DDR2 SDRAM installed into the top slot iMac (Early 2006)
Maximum memory 4GB 2 GB SO-DIMM in each of the two slots* iMac (Late 2006)
2 GB 1 GB SO-DIMM in each of the two slots iMac (17-inch Late 2006 CD)
iMac (Early 2006)
Memory card specifications Compatible:
- 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
Additional notes For best performance, fill both memory slots, installing an equal memory module in each slot.

* The computer will only use a maximum of 3 GB of RAM. For more information, refer to iMac (Late 2006): Memory Specifications.

Installing memory in the bottom slot

Important: When installing SDRAM DIMMs into the computer, press the DIMM up into the slot with your thumbs; do not use the DIMM ejector clips. Trying to push the DIMM into the slot using the ejector clips may damage the SDRAM DIMM.

To install memory into the bottom RAM slot, follow these instructions:

  1. Turn off your computer by choosing Shut Down from the Apple menu.
  2. Disconnect the power cord and all other cables from your computer.
  3. Place a soft, clean towel or cloth on the desk or other flat surface to prevent scratching the display.
  4. Hold the sides of the computer and slowly lay the computer face-down on the towel or cloth.
  5. Using a Phillips screwdriver, remove the RAM access door on the bottom of the iMac, as shown below, and set it aside.
  6. Move the DIMM ejector clips to their fully open position.
  7. Insert your RAM SO-DIMM into the bottom slot, keeping in mind the orientation of the keyed SO-DIMM as shown.
  8. After you insert 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 might 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.

Replacing memory in the top slot

Important: When installing SDRAM DIMMs into the computer, press the DIMM up into the slot with your thumbs; do not use the DIMM ejector clips. Trying to push the DIMM into the slot using the ejector clips may damage the SDRAM DIMM.

To replace memory into the top RAM slot:

  1. Turn off your computer by choosing Shut Down from the Apple menu.
  2. Disconnect the power cord and all other cables from your computer.
  3. Place a soft, clean towel or cloth on the desk or other flat surface to prevent scratching the display.
  4. Hold the sides of the computer and slowly lay the computer face-down on the towel or cloth.
  5. Using a Phillips screwdriver, remove the RAM access door on the bottom of the iMac, as shown below, and set it aside.
  6. Pull the two levers on each side of the memory compartment to eject the memory module that's already installed.

  7. Remove the memory module from your iMac as shown below.
  8. Insert your RAM SO-DIMM into the top slot, noting the orientation of the keyed SO-DIMM as shown below.

  9. After you insert 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 might damage the SDRAM DIMM. There should be a slight click when you seat the memory fully.
  10. Close the ejector clips as shown below.

  11. Reinstall the memory access 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.

Learn more

See Mac computers: About startup tones if you hear tones after installing or replacing memory.

After installing additional memory, you should confirm that your iMac recognizes the new memory. To check the computer’s memory:

  1. Start up your iMac.
  2. Choose About This Mac from the Apple menu. 

The total memory listed includes the amount of memory that originally came with the computer plus the new memory you added, or if all the memory has been replaced, the new total for that memory. For detailed information about the amount of memory installed in your computer, open System Profiler by clicking System Report. Then choose Memory from the Hardware section that appears in System Information.

If your computer doesn’t recognize the memory or doesn’t start up correctly, confirm that the memory you installed is compatible with your iMac and that it's installed correctly by reseating the memory.

Published Date: