Review on 🚀 High-Performance OLOy DDR4 RAM Upgrade for iMac 27-inch & Mac Mini: 64GB (2x32GB), 2666 MHz CL19, 1.2V SODIMM for Immersive Gaming & Faster Performance by Dave Neal

I just received the 64GB RAM kit and installed the SODIMMs along with the 8GB that came preinstalled in my new 2020 5K iMac. You just have to change one of the 4GB to sync it with the other and then install the new RAM. So I got 72GB of RAM @ 2667MHz. I just installed and it works. If something happens I will let you know. Highly recommended and for the price there is no better choice. Update: I've read that mixin banks aren't suitable for iMacs because the RAM modules may run at 2667MHz, but they run on the same channel, so you don't want that. I just removed the original 4GB sticks and ran my iMac with the 64GB OLOy at dual channel 2667GHz. I now have room for a future expansion to 128GB.