Yesterday, the gang at iFixIt (they tear down tech gadgets and look at their innards so you don't have to) disassembled one of the new 21.5-inch iMacs and found (to everyone's surprise) that the memory was upgradeable. It’ the first time Apple has included removable RAM in a 21.5-inch iMac since 2013.
Now Apple says the iMac isn’t user-upgradable, but with the right tools and parts, you can boost your RAM. And iFixIt is offering those tools and parts.
Under Apple's configurations, the 3.0GHz 4K tops out at 16GB of RAM. If you want 32GB, you have to buy the more expensive 3.4 GHz version—a $200 minimum increase, plus $600 for 32GB of RAM.
With iFixit’s iMac Intel 21.5" Max RAM Upgrade Kit, you can quadruple your RAM from 8GB to 32GB for $300. That's just $100 more than what Apple wants to "max out" your RAM at 16 GB on the 3.0 GHz model.
The opening procedure is essentially the same as the 2015 4K iMac. iFixIt has adapted the existing repair instructions to guide you through the installation process for your 2017 iMac.