Help with slow iMac (EtreCheck Report included)

That report indicates that the iMac has 8 GB of RAM, and a 1 TB mechanical hard drive on which about 90% of the space is free. The mechanical hard drive will make booting and launching slower than they would be with a SSD – but you should be able to run multiple applications like Safari and Microsoft Office without crashing and freezing.

If you run Activity Monitor (in the Applications / Utilities folder), and look at the Memory Pressure graph, what do you see there? Green, yellow, or red?

If you see much yellow or red, you might be running some program that is a memory hog or has a memory leak. Keeping hundreds of tabs open in a browser might be one way to use up a lot of memory, and I've also heard of browsers having memory leaks, so if you see signs of excessive memory use, you might want to quit and restart your Web browser.

That report is so garbled that it is hard to fully evaluate. Please see this User Tip on lostling long blocks of text inot a post here:

How to use the Add Text Feature When Post… - Apple Community

When the EtreCheck results window appears, select “Report" from the left-hand pane (scroll down to the bottom of that pane to find):

When its report displays, click the "Share Report" icon from EtreCheck’s toolbar and then "Copy report” from the resulting dropdown.

⚠️ Please DO NOT highlight the text in the report before using Etrecheck’s “Copy report” command—that may garble the formatting and make the report slower and harder to evaluate.

When the Additional Text tool opens, then you use Paste to insert the report:

What I can see in the report is that your entry-level mechanical hard drive is running at nominal speeds for that model drive:

Performance: System Load: 1.06 (1 min ago) 1.43 (5 min ago) 1.54 (15 min ago) Nominal I/O usage: 59.60 MB/s File system: 33.02 seconds Write speed: 80 MB/s Read speed: 73 MB/s

Unfortunately, "nominal" is no longer good enough for modern macOS version. That is the source of your "slows." Adding RAM, were it even feasible in this model without a huge labor charge, cannot make it one iota faster in actual use.

The cost-effective fix it to get a USB-3 external drive with an SATA 6G solid-state drive inside. You clone (not copy) the entire hard drive to the external and use Disk Utility to set the external as your boot volume. The simplest and least costly version of that workaround will give write/read speeds of ~400MB/sec, far faster than what you have now.

claus237 wrote:

Wouldn´t it help to upgrade to a newer OS than Mac OS Big Sur?

With 8 GB of memory and an HDD, no. It'll might even get slower, due to app and OS growth.

8 GB isn't nearly enough to mask the lack of performance of the HDD.

Related: Why is my hard disk drive iMac so slow? - Apple Community

Fastest upgrade here—this side of a replacement Mac—is an external SSD.

Related: Use an external SSD as your startup disk … - Apple Community

I/O means input and output – as when you're loading a file, saving a file, or copying files from one place to another. I'm not sure what I/O usage etrecheck monitors, so it's possible.

I started to put some line breaks into that report (so I could read it). It says there's nominal I/O usage of 59.60 MB/s – which is an awful lot of data if the machine is just sitting there waiting for you to type something into Word. I don't see any Web browsers listed among the "Top Processes Snapshot by Memory"; that seems to put a fork in the idea that it might be a browser memory leak.

In the CPU Usage Snapshot, the top process was contactsd (Apple). I'm guessing that is a daemon (background service) that runs behind the scenes to carry out iCloud synchronization for the Contacts application. Since that application deals with very small amounts of data, I'm not sure why it would be using much of the CPU for long.

Wouldn´t it help to upgrade to a newer OS than Mac OS Big Sur?