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OWC Confirms Support for 64GB of RAM in All Apple 27″ iMac 2017 Models

[Update 06/08: Unboxing and Teardown of the 2017 27-inch iMac with Retina 5K]

Earlier this week at its Worldwide Developers Conference (WWDC), Apple announced updates to its iMac lineup with hardware updates including Thunderbolt 3 ports, more powerful graphics capabilities and faster processors.

Apple also now offers up to 64GB of memory in its 2017 27-inch iMac, however the company only offers configurations up to 32GB memory in the least-expensive base 27-inch model with a 3.4GHz quad-core Intel Core i5 processor.

Fortunately for base model 2017 27-inch iMac owners, OWC has tested and certified through its OWC MaxRAM Certification program that this model, in fact, supports up to 64GB of 2400MHz DDR4 memory.

OWC’s MaxRAM program determines the maximum amount of memory that can be installed in a Mac as validated by a series of comprehensive, in-house laboratory tests. While MaxRAM configurations exceed Apple’s officially supported maximums, all OWC-brand memory upgrades are assured to perform flawlessly and are covered by a Lifetime Advance Replacement Warranty and Money Back Guarantee.

Users looking to upgrade can find memory configurations up to 64GB for the new 27-inch iMac at, with savings of up to $820 compared to Apple factory upgrades!

Haje Kamps of TechCrunch has advice for iMac owners: 

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  • I have a basic “technicolor wheel of death problem” on my 21.5″/2017/iMac with 8GB of memory. It has been recommended that I increase my memory yo alleviate my problem. What is the maximum memory that i can get installed?

  • Can I leave the two 4 gig slots in and add a couple of 16 to the two empty slots for 40 gigs.

  • TOO BAD that it’s only the iMacs that you can upgrade RAM. I do not understand why apple has chosen to force LAPTOP MBPR owners not to be able to upgrade your RAM in your LAPTOP. It doesn’t make sense to me why they are allowing it on one machine and not the others I don’t get it. We are paying a HIGH PRICE for these new machines when they come out and I should be able to upgrade my RAM especially when a MACBOOKPRO can cost more than the iMAC’s ………Apple please go back to the old way of allowing us to upgrade our RAM in the MBPR

  • I’m just curious how you come to the conclusion that these and the prior make MK482LL/A can go to 64GB because I do in fact own a MK482LL/A and I installed 32GB with Major issues. I wish there was a more thorough ex platoon of how these numbers are figured and some science. Like are they dual channel, are they paired in dual channel, why the m395 won’t take 16GB chips nicely, or even 4X8GB I personally appreciate that info and would be much more compelled to spend money but no one I talk to has many answers. I would love to hear feedback on that or a more extensive trick rather than zapping the PRAM on how after modules are in, to allow continuous working conditions in these models. Late 2015 iMac 27″ 3.3QC/8GB ddr3-1867 pc314900/2TB FD/m395 thanks. By the way I’m a music producer it would be nice to hear some focus on that topic rather than cameras.

    • I was just about to upgrade my Late 1015 27″ imac (purchased at Christmas) to 32GB, but if you had probelems now I am nervous about it- what are your thoughts please?

      (the price seems to have shot back up $75 in five days!)

  • Is it preferable to have the same amount of memory in each slot? Does it make a difference if you have 2 with 4GB and the other 2 with 16GB each? Would the Mac function differently and potentially produce more heat?

  • Thanks. Apple should use standard ports and components, not soldered. Why is the very same make and model of RAM purchased from Apple Store two to three times more expensive than in retailers like Amazon?

    • I’m not sure it’s completely true that you’re finding the same make and model of ram. If you are indeed, could you please point me to your source?

  • 27″ 2017 5K–Can I upgrade that to 128gig?

    thanks for the info and help with this article.

  • If the OWC MaxRAM Certification program says that the iMac supports up to 64GB of RAM i would be interested to know the reason why Apple officially says it only supports 32GB.
    What is the reasoning behind this. I mean Apple could ofer their expensive RAM upgrade.

    • While we can’t obviously answer for Apple on that one, it could make sense from an Apple perspective to help their customers out during checkout that if you’re willing to spend $1,400 on 64GB of Apple memory, then you most likely would be better served in stepping up to the next iMac tier in which for $300 you could also upgrade the processor from an i5 to an i7.

      There’s no denying the entry level iMac is a great option, and it’s great to be able to support that iMac with 64GB OWC memory options and tremendous savings vs the factory upgrade price. Thanks for reading!

    • They also said that about the 2008 MBP i have. It was said by apple i believe only 4 GB or 6GB max, but OWC told me i could use 8GB RAM in my 2008 MBP , so i bought it.

      • Did it work? Is yours the unibody or the last of the old style aluminium like my 17″ with all the ports?