How to increase my iMac's memory?

Hey there!

While the memory in iMac isn't user upgradable, typically, the reason for your Mac running slowly isn't due to memory. Rather, if you think your Mac might have a performance issue, you can use this procedure to help gather information on your Mac which will help us troubleshoot your Mac’s problem.

To start, let us know what model your Mac is and what version of macOS you’re using. The simplest way to find out is About This Mac, available by choosing About This Mac from the Apple menu  in the upper-left corner of your screen. 

Next, share a screenshot of your Mac’s storage information. In the Finder, choose Go > Utilities, then double-click the Disk Utility icon. (Disk Utility is located in the /Applications/Utilities folder.) Alternatively, click Launchpad in the Dock, type Disk Utility in the search field, then click the Disk Utility icon. Once Disk Utility is open, take a screenshot of the information it automatically opens to, which will be your startup disk. Next, select View > Show All Devices in Disk Utility and select the non-indented disk entry—it’s at the top of the hierarchy. Then, take a screenshot of the newly selected entry. Upload all screenshots here. 

Finally, let us know what antivirus, VPN, or cleaning software you have installed. 

-Jack

Additional memory won't speed up boot time, app launch time or file saving time. That's all controlled by the speed of the disk you're using.

What model is your iMac, i.e. 27" or 21.5"?

What type of drive does it have and if a HDD what is its rotational speed?

A 21.5" iMac cannot be upgraded memory wise by the user. An Apple Authorized Service Provider will have to do the work. 

If you have a 5400 rpm drive by itself or in a Fusion drive that will be your bottleneck for speed.

Once you give us more info we can suggest possible improvements.

Thanks for the screenshots! I see you're still on macOS Monterey. I would suggest that you upgrade to macOS Ventura, the latest supported version of macOS for your Mac, and see if the issue persists. This Apple Support article should help with the software upgrade: Update macOS on Mac - Apple Support.

Before installing new software, it's a good idea to back up your Mac. If you have an external storage device, you can use it to back up your Mac with Time Machine.

If after upgrading to macOS Ventura you still notice your Mac runs slowly, I'd suggest you setup an external solid state drive (also known as an SSD) as your startup disk. An external SSD as a startup disk can give your Mac additional performance for system responsiveness, apps, startup, and more. To learn more, take a look at this user tip: Use an external SSD as your startup disk … - Apple Community.

Hope this helps!

-Jack

Before upgrading RAM, you might want to check the Memory Pressure graph (in Activity Monitor) while running the workloads that are really slow. The graph is color-coded. Green indicates that you have enough RAM for what you are doing. Yellow indicates that RAM is marginal. Red indicates that lack of RAM is hurting system performance.

Depending on what you are doing, you might find that it's something else (like a slow 5400 RPM hard drive, or a 1 TB Fusion Drive comprised of a slow 5400 RPM hard drive plus a measly 32 GB of flash) that is the source of the slowness.

If it turns out that a lack of RAM is a problem, read on …

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In 2017, there were both Retina and non-Retina 21.5" iMacs, and the Retina ones require faster RAM.

• iMac (21.5-inch, 2017) had a model ID of iMac18,1
• iMac (Retina 4K, 21.5-inch, 2017) had a model ID of iMac18,2

MacTracker says that

• The non-Retina model has an official maximum of 16 GB of RAM, and an actual maximum of 32 GB.
• The Retina model has an official maximum of 32 GB of RAM, and an actual maximum of 64 GB.

It looks like Other World Computing carries RAM for these iMacs – and Crucial does not. Note that the installation of the RAM is something you might want to have handled by a repair shop.

idiotme wrote:

Thankyou memory pressure is green

If Memory Pressure is Green, I would look to either

• A slow startup disk (which could be remedied by adding an external SSD and making that your startup disk), or
• Some sort of software that is installed on your Mac and that is dragging its performance down

So the internal drive is a 1 TB Fusion Drive.

For that model, a 1 TB Fusion Drive would be a combination of

• a slow 2.5" 5400 RPM notebook hard drive
• 32 GB of flash (SSD) space, vs. the 128 GB that Apple originally included in 1 TB Fusion Drives

It looks like you have plenty of free space on the HDD, so that's not an issue. But with only 32 GB of SSD space, there's probably too much competition for the (automatically-assigned) choice "real estate" on the SSD. Some things that could really benefit from being on the SSD are probably being pushed off to the slow HDD simply for lack of SSD room.

It depends on the exact model. Some can be upgraded, others only with a complete teardown, some not at all.

Do Apple > About This Mac and tell us what it says. It will be something like iMac (21.5 inch Mid 2017).

The RAM in a 2017 21.5" iMac is not user upgradable.

see > Install memory in an iMac - Apple Support