Apple iMac (Retina 5K, 27-inch, Late 2015)
Model identifier iMac17,1 All-in-one, from 2015 50 hardware reports
Upgradable
Yes. 4 slots, up to 32 GB seen working.
It takes DDR3-1866 laptop-size sticks (SO-DIMM).
- Slots
- 4 SO-DIMM slots
- Type
- DDR3-1866 204-pin SO-DIMM
- Most seen working
- 32 GB in two or more machines
- Firmware says
- 32 GB maximum
- How sure
- 37 of 37 reports show this layout
See 8 GB DDR3-1866 SO-DIMM on AmazonOpens an Amazon search for this exact spec.
Worked out from 37 hardware reports of this desktop, with Apple's memory specifications for which Macs have sockets. Sources and method. Updated 10 Nov 2026.
4 laptop-size slots
Illustration Questions
Can I upgrade the RAM in the Apple iMac (Retina 5K, 27-inch, Late 2015)?
Yes. 4 slots, up to 32 GB seen working. It takes DDR3-1866 laptop-size sticks (SO-DIMM).
What type of RAM does the Apple iMac (Retina 5K, 27-inch, Late 2015) use?
DDR3-1866 laptop-size sticks (SO-DIMM, 204-pin).
How much RAM can the Apple iMac (Retina 5K, 27-inch, Late 2015) take?
Machines in the reports run up to 32 GB. That matches the 32 GB maximum the firmware reports.
Is this my desktop?
On the Mac, choose Apple menu > About This Mac > System Report. The Model Identifier should read iMac17,1.
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