Got a 2019 iMac 27" with 4 RAM slots. I have 2 x 16Gb and 2 x 32Gb RAM modules. This is how they are installed right now. Is this the most optimal way to install them, or the sequence does not matter?

memory slot repartition 1

memory slot repartition 2


1 Answer 1


In general, for any Mac that’s not core 2 duo, it is hard to benchmark any speed difference no matter how you choose to install ram. (Let alone see it in practice)

Apple publishes manuals for each specific Mac, so let’s see what if your hardware has any recommendations:

The 2019 model doesn’t say anything about order like the 2020 iMac does which says to add up the A channel and B channel and minimize the difference between the two.

  • Your comment on this post makes sense: "All the newest iMacs that have empty slots put the memory in pairs matching left / right so as long as you added your pair left / right but either deeper or shallower from the front glass..." I should perhaps also match left/right. Thanks.
    – lucasart
    Oct 6, 2020 at 13:06

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