Crucial RAM 64GB Kit (2x32GB) DDR4 2666 MHz CL19 Memory for Mac CT2K32G4S266M

As always, Crucial is the best all around brand for Apples (upgradable) computers. Crucial is owned by Micron, a company that Apple themselves uses as an OEM supplier. If youve ever pulled RAM out of a Mac before, you might have seen Micron on the labels. Crucial supplies their own branded components that youd never see inside as OEM on a Mac, but the RAM itself is Micron underneath the Crucial label. Its the brand I always trust most with RAM upgrades on a Mac. Its not the cheapest, and is far from the most expensive. But it is the most dependable. And trust me, you want dependability if youre going to go through the hassle of upgrading the memory on a 2019 iMac.

Excellent! Work perfectly with my iMac.

Easy to install, great value for the money, what else do you need :)

I upgraded my iMac RAM to 40gb total from the original 8gb purchased. Buying the additional RAM from somewhere other than Apple will save you a boat load of money. I researched that Crucial was one of the better brands to purchase and were compatible with Macs.

Holy Multiple Windows at the same time Batman!!!!!!!! :). Wooooow!!!!! Worked as advertised :)

Great stuff

Works for 27inch iMac 4K Retina. Had to try multiple slot configurations but eventually it worked perfect.

Works ok for me.

These RAM chips worked in my base model 2017 iMac 27. I placed the stock apple chips in the top two slots, and the crucial chips in the bottom two. I never experienced any problems.

Got these to expand the memory in my 2017 5k iMac. Unlike other reviews, my machine works best when I left the OEM memory in their original slots. Otherwise they work just fine, fit perfectly, and arrived in great condition.