iMac (27-inch, Late 2012): Installing or replacing memory
Summary
Learn how to install additional memory or replace the memory in your iMac (27-inch, Late 2012) computer.
Products Affected
Note: The iMac (21.5-inch, Late 2012) has no user-accessible memory compartment. Memory replacement on the iMac (21.5-inch, Late 2012) must be done by an Apple Retail Store or Apple Authorized Service Provider.
General Information
iMac (27-inch, Late 2012) computers have four SO-DIMM DDR3 SDRAM (Synchronous Dynamic Random-Access Memory) slots located in a compartment on the rear of the computer just above the AC power cord receptacle. You can use 4 GB or 8 GB SDRAM SO-DIMMs of 1600 MHz DDR3 memory in each slot. The maximum amount of memory you can install in the computer is 32 GB (an 8 GB SO-DIMM in each slot).
Note: Only use SO-DIMMs that meet certain criteria.
Installation
- Turn off your computer by choosing Shut Down from the Apple () menu.
- Disconnect the power cord and all other cables from your computer.
- Place a soft and clean towel or cloth on the desk or other flat surface to prevent scratching the display.
- Hold the sides of the computer and slowly lay the computer face-down on the towel or cloth.
- Open the memory compartment door by pressing the small black button located just above the AC power port.
- The memory compartment door will open as the button is pushed in. Remove the compartment door and set it aside.
- 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.
- Once the memory cage is released:, pull the memory cage levers toward you, allowing you to access each individual DIMM slot.
- Remove a DIMM by pulling the module straight up and out .
- Replace or install a DIMM by setting it down into the slot and pressing firmly until you feel the DIMM click into the slot.
- Once you have all of your DIMMs installed, push the memory cage levers back into the housing until they subtly click back into place.
- Replace the memory compartment door. There is no need to depress the compartment door release button when replacing the compartment door.
- Place the computer in its upright position. Reconnect the power cord and all other cables to the computer, then start up the computer.

Note: There is a diagram on the underside of the compartment door showing the memory cage levers and the orientation of the DIMM.
Additional Information
See iMac (Mid 2007) and later models: About new startup tones if you hear tones after installing or replacing memory.
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