Install and replace memory in your Mac Pro (2019)
Find out how to remove and install memory in your Mac Pro.
Mac Pro (2019) has 12 DIMM (memory) slots that support up to 1.5 TB of 2,933 MHz memory when all 12 slots are full using DDR4 ECC DIMMs.
8-core, 12-core and 16-core Mac Pro models support up to 768 GB of memory.
Before you begin
You can use either R-DIMMs or LR-DIMMs with your Mac Pro, but you can’t mix these memory types. To check if you have R-DIMMs or LR-DIMMs installed and to view your memory status, choose Apple menu > About This Mac, then select the Memory tab.
Make sure you use the same type of memory when installing additional DIMMs or replacing DIMMs. Find out more about Mac Pro (2019) memory specifications.
Apple recommends using Apple-approved DIMMs. You can purchase memory upgrade kits by visiting an Apple Store or Apple Authorised Reseller. If you need to order replacement memory, contact Apple.
RAM availability varies by country and region.
Check supported configurations
Mac Pro supports up to 12 DIMMs installed in configurations of 4, 6, 8, 10 or 12 DIMMs, as shown in the images below. These images can also be found on the inside of the DIMM covers. For maximum performance, install DIMMs in a 6- or 12-DIMM configuration. If your DIMMs aren’t identical in capacity, find out how to install DIMMs of mixed capacities.
A 1-DIMM configuration is for diagnostic use only.
4 DIMMs
6 DIMMs
8 DIMMs
10 DIMMs
12 DIMMs
Each number represents a DIMM slot. For each DIMM configuration, only insert DIMMs into the dark grey slots and leave the light grey slots empty.
Installing R-DIMMs of mixed capacities
If you use 32 GB DIMMs with other capacities, such as 8 GB or 16 GB, they must be installed according to these requirements:
Only use R-DIMMs.
Use a supported configuration.
Install the 32 GB DIMMs in the first slot of each channel pair.
Not all memory channels are used for every DIMM configuration. For example, an 8-DIMM configuration uses channels A, B, D and E.
DIMM Channels
In the image above, the 12 slots on the left form 6 channel pairs as shown on the right. Each channel pair has slots designated DIMM 1 and DIMM 2.
Installing LR-DIMMs of mixed capacities
To install LR-DIMMs, all DIMMs must be the same capacity. Use the slots determined by your configuration.
If you install LR-DIMMs of mixed capacities, your computer will not start up.
Remove or install memory
Find out how to remove the housing of your Mac Pro, remove DIMMs and install DIMMs.
Remove the housing or memory access door
Follow the steps to remove the housing on Mac Pro (2019) or the access door on Mac Pro (Rack, 2019).
Mac Pro (2019)
Wait approximately 5–10 minutes for the computer to cool down.
Unplug all cables except the power cable from your computer.
Touch the metal housing on the outside of the Mac Pro to discharge any static electricity, then unplug the power cable.
Always discharge static before you touch parts or install components inside your Mac Pro. To avoid generating static, don’t move around the room until you’ve finished installing the memory and have slid the enclosure back onto the computer.
Flip the top latch up, then twist left to unlock the housing.
Lift the housing straight up and off the computer. Carefully set it aside.
Mac Pro won't turn on when its cover is removed.
Mac Pro (Rack, 2019)
Wait approximately 5–10 minutes for the computer to cool down.
Unplug all cables, except the power cable, from your Mac Pro.
Touch the metal housing on the outside of the Mac Pro to discharge any static electricity, then unplug the power cable.
Always discharge static before you touch parts or install components inside your Mac Pro. To avoid generating static, don’t move around the room until you’ve finished installing memory and have installed the access door back onto the computer.
Stand your Mac Pro on its end.
Push in the top of the latches, then pull the latches to remove the access door.
Remove DIMMs
Your Mac Pro comes with DIMMs preinstalled in some or all of the DIMM slots. Before you can install memory, you may need to remove some of the DIMMs to match a supported configuration or to meet mixed capacity R-DIMM installation requirements.
Slide each lock to the left to unlock and open the DIMM covers.
Remove the DIMM covers.
Locate the DIMM(s) you want to remove. Each slot is labelled with a number. Push down on the DIMM ejectors on each end of the DIMM, which slightly raises the DIMM out of the slot.
Use your thumb and index finger from each hand to gently grip the DIMM at each end, then carefully remove the DIMM by pulling the DIMM straight out of the DIMM slot. Don’t twist or force the DIMM out of the socket as damage may occur.
Place the removed DIMMs into an electrostatic discharge (ESD) protective bag.
Install DIMMs
Locate an empty DIMM slot.
If possible, use canned air to blow dust out of the DIMM slot. Keep the can vertical.
Hold the DIMM ends gently and insert it into the slot. Make sure the DIMM is aligned with the slot before applying any force to insert it. When you insert the DIMM, make sure you follow these guidelines:
Don’t force the DIMM. If the DIMM doesn’t insert, verify that the notch and connectors are aligned with the notch in the DIMM slot.
Don’t rock the DIMM into the seated position.
Don’t bend or twist the DIMM when you insert it.
Insert the DIMM gently until the bottom edge of the DIMM is touching the gold contacts, then apply more force to fully seat the DIMM. The DIMM ejectors will click into place once the DIMM is fully seated.
Replace the DIMM covers. Push down on the left-hand side of the covers until they click into place.
If you don’t replace the DIMM covers, system performance may be affected.
Reinstall the housing or top cover
Follow the steps to reinstall the housing on Mac Pro (2019) or the top cover on Mac Pro (Rack, 2019).
Mac Pro (2019)
Lower the housing over the Mac Pro.
Top: locked position (dots match)
Top: Locked position (dots match)
Bottom: Unlocked position (dots do not match)
Connect the power cable, display and any other peripherals.
Mac Pro (Rack, 2019)
Reinstall the access door.
Connect the power cable, display and any other peripherals.
Verify your memory
To check the status of your memory, choose Apple menu > About This Mac, then select the Memory tab.
If your DIMMs should be configured in different slots to maximise performance, macOS will notify you with recommendations for which slots to use for your currently installed DIMMs.
Other configurations
If you want to test any single channel or the DIMM itself, you can use a 1-DIMM configuration by installing a single DIMM into the first slot of a channel. If you want to test the second slot of a channel, install DIMMs into both slots of a channel.
Learn more
If you’ve received a replacement part from Apple, follow the steps to send your original part back to Apple.
Look up Mac Pro (2019) memory specifications.
Find out more about some of the PCIe cards you can install in your Mac Pro.
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