Chosen Solution
I’d like to add a 16GB RAM to the existing 8GB (2x4gb) stock RAM in my iMac 27" late 2015. Wondering this will pose any issues or will I now simply have 24gb of RAM? Many thanks, Patrick
You really need to stick with two 8GB SO-DIMM’s (total of 16 GB) with your current 8 GB that will get you 24GB of total RAM! Your system has four RAM slots so you’ll not have any issues fitting them. Just make sure you get the correct spec’ed RAM. Update (07/31/2020) It’s a matter of pairs as you are using both channels. Sadly, Apple doesn’t offer the details other PC makers do on the iMac’s. Surprisingly they did on the new MacPro memory covers!
You don’t see an odd number of DIMM’s do you? That holds true here Two of that and Two of them or just Four of these. Does that help explain it? FYI - Older iMacs only had one Memory Channel and used Banks instead!
