Apple iMac (Retina 5K, 27-inch, 2017)
Model identifier iMac18,3 All-in-one, from 2017 57 hardware reports
Upgradable
Yes. 4 slots, up to 64 GB seen working.
It takes DDR4-2400 laptop-size sticks (SO-DIMM).
- Slots
- 4 SO-DIMM slots
- Type
- DDR4-2400 260-pin SO-DIMM
- Most seen working
- 64 GB in two or more machines
- Firmware says
- 32 GB maximum (often wrong, so we show what machines run)
- How sure
- 33 of 34 reports show this layout
See 16 GB DDR4-2400 SO-DIMM on AmazonOpens an Amazon search for this exact spec.
Worked out from 34 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, 2017)?
Yes. 4 slots, up to 64 GB seen working. It takes DDR4-2400 laptop-size sticks (SO-DIMM).
What type of RAM does the Apple iMac (Retina 5K, 27-inch, 2017) use?
DDR4-2400 laptop-size sticks (SO-DIMM, 260-pin).
How much RAM can the Apple iMac (Retina 5K, 27-inch, 2017) take?
Machines in the reports run up to 64 GB. The firmware reports a maximum of 32 GB, a figure that is often wrong.
Is this my desktop?
On the Mac, choose Apple menu > About This Mac > System Report. The Model Identifier should read iMac18,3.
More in the Apple iMac
- iMac (21.5-inch, Mid 2011) (iMac12,1)
- iMac (27-inch, Mid 2011) (iMac12,2)
- iMac (20-inch and 24-inch, Mid 2007) (iMac7,1)
- iMac (20-inch and 24-inch, Early 2008) (iMac8,1)
- iMac (21.5-inch and 27-inch, Late 2009) (iMac10,1)
- iMac (20-inch and 24-inch, Early and Mid 2009) (iMac9,1)
- iMac (27-inch, Late 2013) (iMac14,2)
- iMac (21.5-inch, Late 2013) (iMac14,1)
- iMac (21.5-inch, Mid 2010) (iMac11,2)
- iMac (Retina 4K, 21.5-inch, 2017) (iMac18,2)
- iMac (27-inch, Mid 2010) (iMac11,3)
- iMac (Retina 5K, 27-inch, Late 2015) (iMac17,1)