My late 2013 iMac is slowly driving me mad with how slow it's become over the years.

I think we have an elephant in the room:

Top Processes Snapshot by CPU:

Process (count) CPU (Source - Location)

utilityData 96.56 % (? - ~/Library/utilityData/utilityData.app)

Other processes 51.58 % (?)

EtreCheck 17.54 % (App Store)

Google Chrome Helper (GPU) 7.70 % (Google, Inc.)

Mail 6.60 % (Apple)

I'll hazard a guess that your adware is causing that, and throwing RAM at that won't make it go away. If you cannot get EtreCheck to clear those two entries, then get MalwareBytes and start with the free version. Get MalwareBytes only from the developer's site:

https://www.malwarebytes.com/mac/

I am also very concerned with your hard drive's speeds. Although a 7200rpm drive, it posted slower read/write speeds than our old 2011 iMac with a 5400rpm drive:

Yours iMac's 7200rpm drive:

Performance:

System Load: 2.79 (1 min ago) 2.28 (5 min ago) 2.07 (15 min ago)

Nominal I/O speed: 2.21 MB/s

File system: 112.68 seconds

Write speed: 39 MB/s

Read speed: 73 MB/s

Our older iMacs' 5400rpm drive:

Performance:

    System Load: 1.62 (1 min ago) 1.67 (5 min ago) 1.87 (15 min ago)

    Nominal I/O speed: 0.05 MB/s

    File system: 38.28 seconds

    Write speed:  112 MB/s

    Read speed:  91 MB/s

Again, that may be a adware issues so we have to get those adware invaders out of the way to get a good picture of your overall performance picture.

Download and run Etrecheck. Etrecheck is a diagnostic tool that was developed by one of the most respected users here in the ASC and recommended by Apple Support  to provide a snapshot of the system and help identify the more obvious culprits that can adversely affect a Mac's performance.

Copy the report

and use the Add Text button to include the report in your reply. How to use the Add Text Feature When Posting Large Amounts of Text, i.e. an Etrecheck Report

Before running Etrecheck assign Full Disk Access to Etrecheck so that it can get additional information from the Console and log files for the report:

Then we can examine the report and see if we can determine what's causing the problem..

I advise installing more RAM.

Your year and model iMac can take UP to 32 GBs of RAM.

RAM is user installable and is relatively easy to install.

You MUST use THE EXACT RAM that your model iMac is spec'd for.

Proper spec’d and reliable Mac RAM can ONLY be purchased from online Mac RAM sources Crucial memory ( crucial .com ) or OWC, aka, Other World Computing ( macsales.com ).

When buying RAM for Macs from Crucial memory,purchase ONLY directly from the Crucial memory website.

NOT from some other online source.

https://eshop.macsales.com/shop/memory/iMac/2012_27/DDR3L

RAM modules are, relatively, easy to install.

https://eshop.macsales.com/installvideos/memory-imac27late2013/iMac14-2/

Also, uninstall and stop using Google Chrome as it is a major Mac hardware/software resource hog.

Use Mozilla Firefox or Waterfox Web browsers, instead.

Best of Luck to You!

The WhatsApp app is using up about a third of your CPU's resources. Either uninstall it or only run it when you need it to check for incoming.

Apple only offers the minimum amount of RAM to operate the Mac and it's included apps. I suggest you upgrade to 16GB with a couple of 4 GB modules from Crucial.com or MacSales.com. [

Another approach to speed would be to get an external SSD and boot from it. It would greatly speedup your boot time as well as launch time for apps and opening of files on the SSD. Your internal HD could be used for additional storage of seldom used files.

I have the following setup to boot from when I want to run an old system or a beta system:

The SSD is from MacSales and was ~$130 for 1 TB. The SATA to USB3 adaptor is from Amazon.com. My 2017 27" iMac with an SSD boot drive boots up in 25-30 seconds. The external SSD boots from 45-50 seconds.

There are more attractive USB 3 SSD units available at additional cost as the USB 3 enclosures do cost more than the just the adaptor. I also have this USB 3 dock from MacSales for housing two 1TB SSDs for external storage:

So there are a number of avenues you can take to greatly improve the speed of your iMac.

Just some food for thought.

First of all: clear ALL caches. There are way too many details to go into, so just Google it or find a YT vid. Google Chrome has it's own way of clearing the cache, so go into the settings and navigate to your cookies and cache.

Second Trial: eliminate browser add-ons. Some of them cause lag in the performance of the app, especially in Safari, but also in Chrome and Firefox. The Grammarly add-on for Safari will slow you down from 60 MPH to a slow walk.

If these tricks don't work, you need to consider adding RAM or swapping out your HD with an SSD. This is super-easy. But again, get the details on You Tube. There are dozens of videos on how to do it yourself. I've done it on my MBP and iMac 27 (both mid-2011) and solved all my problems. R/W speeds are 385/350 compared to the iMac standard 5400 HD speeds of 31/25. The difference is night and day. On your iMac, you will need to use an external enclosure (Lacie Rugged) with a ThunderBolt 1/2 soldered wire to get the full speed conversion and set it as your boot drive after you do a clone through Disk Utility.

Here is the vid to clone, but skip the last part cause you cannot install internally on an iMac unless you're pro status: https://www.youtube.com/watch?v=lfJrAcnHN2g

Here's the vid to set up the external enclosure and boot settings.:

https://www.youtube.com/watch?v=VyZlDwV1AOY

Good luck!

One reason is Chrome is a MAJOR RAM hog. To monitor where you RAM is being used, please begin using Activity Monitor. Directions on how to use it are in Activity Monitor to read System Memory and determine how much RAM is being used

The app is located in Applications-Utilities-Activity Monitor.

macOS, alone, can eat up a sizable amount of the available installed base 8 GBs of RAM.

Google Chrome is a RAM and other Mac resource hog and so are Adobe Apps.

At this stage your Mac is being starved for RAM.

Adobe Photoshop, FYI, should always, ALWAYS be running alone, by itself, with no other heavy background apps running.

Unless, you decide to install the full 32 GBs of RAM into your iMac.

Otherwise InDesign and Illustrator with sufficient installed RAM, both of these can run side by side.

It is what it is.

Gone are the days when you could run a Mac OS on 2-4 GBs of RAM.

Those days are gone.

AND you just cannot run the entire Adobe Creative Suite all at the same time with ONLY 8 GBs of RAM, any longer, when you have a Mac that uses physical installed RAM for VRAM for the Mac’s GPU.

No way.

NOT with only 8, or even, 16 GBs of physical RAM installed.

Sorry.

Try booting into Safe Mode (Use Safe Mode to isoloate issues with your Mac) and then reboot normally. You've not rebooted for 6 days and if you have any damaged temporary swap, cache or system files rebooting can clear them out and improve performance.

NOTE: Safe Mode boot can take up to 10 minutes as it's doing some system cache cleaning, volume verifying and directory repairing. 

More frequent reboots don't need to be Safe Mode type.

Your last Etrecheck report showed quite a bit more RAM was nearly used up.

Over 6 GBs of RAM, used.

Mac OS, by itself, will go back and forth using the Lion's share of that base amount of RAM.

Your Mac does NOT have a sufficient amount of RAM for any heavy duty applications, like Adobe apps. Period!

My 10-year old iMac has 16 GBs installed and is running better than your 6-year old iMac.

Adding RAM years, ago helped, but I am, also, NOT running the latest and greatest macOS, versions, either.

I am running OS X 10.11.6 El Capitán and OS X 10.9.5 Mavericks and on occassion, OS X 10.8.5 Mountain Lion.

macOS Catalina IS probably taxing all of your iMac's hardware resources.

AND spinning mechanical hard drives do slowdown with age with constant read/writes to them.

I use a 10-year old iMac and an external SDD gave it a new life about two years, ago!

BUT extra RAM was an noticeable boost, too!

Also, I never load up any of my Mac's hdrives with any type of garbage are/crawpware!

Have you simply tried running your iMac, too, with no other drives connected to see if one of your other drives could be the culprit?

When mechanical drives start having issue, this can bring down system performance, too!

You can test each external drive for issues by connection up each one individually and test the entire system for any noticeable slowdowns.

This is my story and I am stickin’ to it!

Use EtreCheck to rid the computer of the installed AdWare. After clearing the AdWare, restart the computer and check for improved performance.

my splitty is a 1962 wrote:

OK thanks, but what I don't understand is why is so much RAM being used ..........

From your EtreCheckPro report.

Adware:

Launchd: ~/Library/LaunchAgents/com.updater.mcy.plist

Executable: ~/Library/Application Support/updater_mcy/updater_mcy -rm check -uip

Reason: Adware name match

Launchd: ~/Library/LaunchAgents/com.updater.watch.mcy.plist

Reason: Adware name match

Your last Etrecheck-report writing a lot of VideoGuard from cisco!

A little Google searching tell me that VideoGuard is a type of Adware?

I can not believe that British SKY is the trouble on your iMac computer?

But give it a try and uninstall VideoGuard for a time!

You, have some, problems, with Safari Chrome,and Firefox?

Why not use Opera Browser,so is more faster,and quicker, than the other Browsers?

While the RAM is needed.

You didn't waste $75.

Clearly, RAM may or may not be causing all of your iMac’s issues.

Did you properly erase ALL of the adware and any other garbageware you were told to properly uninstall?

Are you sure all of the adware, garbageware and any antivirus software is totally gone from your iMac?

After all of this time of trying to troubleshoot your iMac, I think it is becoming time to just perform the ”nuclear” approach, now.

You need to completely back up this iMac to a backup drive, and then use the recovery partition to perform a complete erase and re-format and re-partition of this iMac's hard drive and re-install macOS and either add back or completelly reinstall all of your third party applications one at a time and then restore all of your other saved data.

There isn't anything else left to try at this point.

I do not have the patience or my own documentation any longer to fully detail a complete hard drive erase/format and reinstallation of macOS and all of your applications and data.

Hopefully one of the other regular contributors here already have these procedures still documented to assist you in bringting your iMac back to a default starting point to get your iMac back to a working order.

I am all out of other ideas as to why your iMac is performing so badly.

Best of Luck!

Do you have to have VideoGuard installed? You might try uninstalling according to the developer's instructions and run for a bit without it. It seems to have a lot of files scattered throughout your system.

Reinstall the MacOs Sierra 10.12.6 on this issue?

From your Time Machine Copy,or from the App Store?

You have some Adware on your 2013 iMac!

I am not,some, experts,on this,but an reinstall wiil do some progress!

Reinstall the iMac,and it will run some smottly!