How much RAM can I put into my 2019 27 inch iMac? Is there a limit to how much is worthwhile?

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Level 1

9 points

How much RAM can I put into my 2019 27 inch iMac? Is there a limit to how much is worthwhile?

The 2019 27-inch iMac (5K Retina) officially supports up to 128 GB of RAM, though Apple initially advertised it as supporting up to 64 GB. It has four SO-DIMM slots, and you can install either 4 GB, 8 GB, 16 GB, or 32 GB sticks of DDR4 2666 MHz RAM.

How much RAM is worthwhile?

It depends on your usage:

16 GB: Great for general multitasking, web browsing, media consumption, and light creative work.
32 GB: Ideal for more demanding tasks like video editing, photo editing, and running virtual machines.
64 GB - 128 GB: Overkill for most users but very useful for professionals working with 4K/8K video editing, 3D rendering, heavy computational tasks, and scientific simulations.

For many users, 32 GB will cover most tasks, but if you handle resource-intensive work, 64 GB or even 128 GB might be beneficial. RAM is relatively cheap for this iMac, and since you can easily install it yourself, it’s a no-brainer to me to upgrade to 72GB initially and now to 128GB.

My 2019 iMac Specs:

3.7 GHz 6-Core Intel Core i5 processor
Radeon Pro 580X 8 GB graphics card
512 GB SSD (no Fusion or mechanical drive)
8 GB RAM (4GB x 2)

In February 2020, I ordered the Crucial 64GB Kit (32GBx2) DDR4 2666 MT/S CL19 SODIMM 260-Pin Memory - CT2K32G4SFD8266 for $309.99 from Amazon. OWC, Newegg, and Crucial are also reputable sellers — but online reviewers warned about irritating incompatibilities with some brands of RAM other than Crucial, so I stuck with Crucial, which is also allegedly an OEM supplier to Apple for memory.

With the 8GB that came with the Mac, the 4 slots filled up to 72GB. It worked great for a long time. However, if I have many browsers open (Chrome, Safari, Brave, Explorer, etc.) with many tabs and other apps, the iMac can still slow down. So, I'm upgrading to 128GB total RAM by ordering 2 more Crucial 32GB DIMMs as above. The kit now, in September 2024, is about $130 directly from Crucial.

I just upgraded this Mac to Sequoia OS, so it should still last a while, and it's still my favorite screen at 27" 5K, so it’s worth it to me to upgrade.

Posted on Sep 17, 2024 7:22 AM

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Answer 1

den.thed

Level 10

82,342 points

Sep 17, 2024 7:45 AM in response to pt0600

What is your actual RAM usage under normal use..?

To check open your Activity Monitor and click on the Memory tab.

If the RAM is running in the green, then adding more will not help and would be a waste.

To look for other reasons why your iMac is slowing down,

Download and run the free version of EtreCheckPro, from > https://etrecheck.com/en/index.html

Then post the Report, as per > How to use the Add Text Feature When Post… - Apple Community

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Answer 2

Allan Jones

Level 9

72,176 points

Sep 17, 2024 10:56 AM in response to pt0600

+1 on EtreCheck. Most "slow iMac" complaints we see are due to storages issues, not a paucity of RAM. Adding RAM will never speed up an underperforming drive.

Etrecheck will check drive performance and tell use exactly which the iMac storage options you have. We have benchmarks with which to compare yours to "normal." Etrecheck is the development of a long-serving and trusted ASC contributor. It is a reporting app, not a "fix-it” app, expressly for displaying information in these forums to help us help you remotely. It will not reveal any personal or secure information.

My 2017 iMac 27 is quite responsive with 16GB RAM. It never shows being starved form RAM.

Check if your Mac needs more RAM in Activity Monitor - Apple Support

Etrecheck will check drive performance and tell use exactly which the iMac storage options you have. We have benchmarks with which to compare yours to "normal." Etrecheck is the development of a long-serving and trusted ASC contributor. It is a reporting app, not a "fix-it” app, expressly for displaying information in these forums to help us help you remotely. It will not reveal any personal or secure information.

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