RAM configuration 4GB + 16GB possible?

Discussion in 'Mac mini' started by tombaja, Dec 4, 2018.

  1. tombaja macrumors newbie

    Dec 4, 2018
    La Paz, Mexico
    In a MacRumors article about the RAM upgrade process of the 2018 Mac mini it is written: “The process allows users to install up to 64GB of RAM, using any combination of 8GB, 16GB, or 32GB DDR4-2666 SODIMM RAM modules, which are available from third-party brands….” Does “..any combination..” mean that I can install a 4 GB RAM module together with a 16GB RAM module? In this case I could re-use one of the installed 4GB RAM module together with a new 16GB RAM module, achieving a capacity of 20GB of RAM.
  2. F-Train macrumors 65816

    Apr 22, 2015
    NYC & Newfoundland
    If you do a search, you'll find several threads, and posts within threads, about this very issue.
  3. Spectrum macrumors 65816


    Mar 23, 2005
    Never quite sure
    Yes 20GB works, but GPU performance may be slightly degraded. Needs more testing to confirm...
  4. hsadler macrumors newbie

    Jul 7, 2008
    And when price 'finally' drops on 32 GB, you should be able to replace the other 4 GB with a 32 GB giving you 48 GB. Should work, but I can't guarantee.
  5. SoCalReviews, Dec 7, 2018
    Last edited: Dec 7, 2018

    SoCalReviews macrumors 6502a

    Dec 31, 2012
    It might work but it's generally not recommended. You usually want to install the exact same brand and type of RAM sold in matched pairs into your computer. The reason is that different RAM even of the same type can have different performance characteristics. The system will read and write to the memory slots with certain performance expectations based on the specs of each RAM stick read and stored by the computer BIOS.

    It depends on the system but usually either the BIOS will run off the specs of the first bank it reads or it will set its performance expectations to run off the lowest spec RAM in either slot. A difference in specs or read and write performance between the two RAM sticks could cause problems such as beach balls, system lockups, degraded video performance, etc..

    You could always try the combination out and see if it works and it may seem to work fine but it's just not recommended if you want optimum speed and reliability. This is the kind of issue that makes companies like Apple cringe over product warranty returns from customers who blame their Mac problems on faulty product when it's often user related failure due to bad third party upgrades.

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4 December 4, 2018