Question 1

I have 16G installed in in my 2017 27" retina iMac.  If I purchase a 32G kit and install it with the 16G (giving me a total of 48G) will this work?

Accepted Answer

It should. The max RAM for that model is 64GB, and I've mixed different sized RAM sticks in the same model iMac before without a problem. Just try to make sure you get RAM with the same speed and timings.

Question 2

Have the 2017 27" iMac 3.5 GHz with 8GB (4x2) installed and wanting to increase it.  According to Apple specs it says the memory is 3.5GHz
8GB (two 4GB) of 2400MHz DDR4 memory; four SO-DIMM slots, user accessible, Configurable to 16GB, 32GB, or 64GB.  If I add 32 GB to the 8 will it only use 32GB?

Accepted Answer

You can only use 4GB, 8GB, or 16GB DIMMs, you cannot use a single 32GB DIMM. You have two empty slots, so if you want to add to what you already have you can add 2x4GB, 2x8GB, or 2x16GB. I had the same as you, two 4GB DIMMs for 8GB. Then I added 2x16GB DIMMs for a total of 40GB. That’s been plenty of memory for me.

Brand	Crucial
Model	CT2K16G4S24AM
Type	260-Pin DDR4 SO-DIMM

Compatibility	For Apple iMac
Capacity	32GB (2 x 16GB)
Speed	DDR4 2400 (PC4 19200)
CAS Latency	17
Voltage	1.2V
ECC	No
Buffered/Registered	Unbuffered

Crucial 32GB Kit (16GBx2) DDR4 2400 MT/s (PC4-19200) DR x8 SODIMM 260-Pin for Mac - CT2K16G4S24AM

Learn more about the Crucial CT2K16G4S24AM

Customer Reviews of the Crucial CT2K16G4S24AM

Warranty & Returns

Warranty, Returns, And Additional Information

Warranty

Return Policies

Manufacturer Contact Info

Item#: N82E16820156169