I'm hoping we have someone who is at least a pseudo-expert on iMacs and iOS. I have an iMac that is about seven or eight years old. In the past year I have increasingly been getting the colored circle of death. I've done research off and on with respect to the issue and made some changes as suggested with only temporary relief. As you know, this means my computer is aggravatingly slow and lagging. Does someone have some suggestions to try to remedy this? Thank you in advance.

My guess is the most likely problem is that it is “seven or eight years old”.

More info would be helpful…

Which OS version?, Processor?, Memory?, What program(s) are experiencing the slow downs?

Newer versions of programs expect newer OS versions and newer hardware so older hardware may be getting overwhelmed.

Newer OS versions take advantage of newer hardware and put a heavier load that may choke older hardware.

I always start by resetting the PRAM.

Shut down your Mac, then turn it on and immediately press and hold these four keys together: Option, Command, P, and R. You can release the keys after about 20 seconds, during which your Mac might appear to restart. On Mac computers that play a startup sound, you can release the keys after the second startup sound.

Also, unplug it for about a minute. Not just turned off, but unplugged. There is some memory that doesn't clear unless unplugged.

Replace it with a M1 Macbook Air.

Before doing so, ensure your info is uploaded to the cloud under your appleid. This requires that you subscribe to an apple storage plan. Make doubly sure your photos music and documents are in icloud.

If you cannot open the old apple hardware and upgrade with ssd and more ram, just replace it.

Max out the internal memory. If you're running Time Machine backup, turn it ff and eject that disk. I have had occasional super slow operation when the backup disk is nearly full. Increase your internal hard drive size.

There are ways to see what is running in the background. Do some poking around in that.

Set your email accounts to stop updating. You can select the frequency, and if it is too often it can bog things down. If it updates only when you open the app that should be good enough.

Use Apple apps. Safari, Mail, Numbers, Pages, not outside apps.

I’d try backing up all files you want to save, on an external drive and then do a full reformat/reinstall of the Mac OS

You have to pick your Mac OS version from the drop down list:

Erase and reinstall macOS

Have you upgraded the RAM, by any chance? Bad RAM can cause a Mac to behave like this. If you haven't, I'd agree with the other posters here and I'd implement their advice from least to most invasive. Reset PRAM first, if no change, reinstall OS, if no change, upgrade and max out your RAM.

Thank you all for your input. It is greatly appreciated. I've implemented a number of things suggested both here and on another forum and appear to have eliminated my problem, at least for now.