At the completion of comprehensive compatibility testing, OWC is pleased to announce that the 2019 27-inch iMac Retina 5K is able to be user-upgraded to a mammoth 128GB of 2666 MHz DDR4 memory. The screenshot below shows a variety of utilities all showing one of the new iMacs fully loaded with RAM:

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Here are the prices and links for the memory upgrades now available for the 27-inch Retina 5K iMac:

64GB (2 x 32GB) – $579.99

96GB (2 x 32GB + 2 x 16GB) – $794.99

128GB (4 x 32GB) – $1099.99

Upgrades of the 27-inch iMac can be done by anyone, and require simply opening a small hatch on the back of the unplugged computer and inserting new DIMMs in the open or existing slots.

After completing the upgrade, you’ll be able to enjoy the sight of Activity Monitor showing 128 GB of physical memory and almost no memory pressure (see screenshot below). The upgrade is perfect for those who use RAM-hungry applications.