In case you’re wondering what type of memory you need to go out and buy to upgrade your shiny new iMac, Apple is laying it all out for you in a support document updated December 20, 2012.The computer company says to only use SO-DIMMs that meet certain criteria with your Late 2012 iMac, and remember that you can only upgrade the 27” model yourself. For the 21.5” version, you’ll need to box it up and take it to your local Apple store.
Right, so the RAM that works with the new Late 2012 iMacs must sport the following features, Apple says: PC3-12800; Unbuffered; Nonparity; 204-pin; 1600 MHz; DDR3 SDRAM.
The Mac maker carefully points out that some DIMMs don’t work with Late 2012 iMacs. These sport the following characteristics: Registers or buffers; PLLs; ECC; Parity; EDO RAM.
Again, the latter RAM model is not supported on the new iMacs. Happy upgrading!