Slow running Mac with high CPU usage and unresponsive Illustrator

Your problem is VERY likely caused by the third part party antivirus app you have installed, TotalAV. Mac OS does not require nor does it benefit in ANY way by installing any of the following types of third party apps:

• Antivirus
• Cleaning
• Security
• VPN
• Maintenance

Please locate the developers uninstall instructions for TotalAV and follow to the letter. After uninstalling please restart the computer in Safe Mode and then restart normally and retest the computer.

In addition, note your computer is getting kind of old at this point and still has the original Fusion Drive installed which could also contribute to the problem. All HD's fail and yours is not about 7 years old. You can check the HD's health by doing the following:

1. Click the Apple menu () in the top-left corner and select About This Mac.
2. Click System Report.
3. In the left sidebar, navigate to the Hardware section and click Storage.
4. Select your drive from the list. The S.M.A.R.T. status will be listed in the lower section of the window. 

These data points:

Performance:

System Load: 1.94 (1 min ago) 2.49 (5 min ago) 2.20 (15 min ago)

Nominal I/O usage: 10.89 MB/s

File system: 18.85 seconds

Write speed: 723 MB/s

Read speed: 2641 MB/s

Indicate that your Fusion drive system is healthy and running at expected speeds for that model—for now. To go any faster using an external drive you will, as rkaufmann87 wisely points out, need a high-speed external Thunderbolt 3/4 SSD, not the more common USB3 models using an SATA 6 SSD. Te latter will drop your writes and reads to under 600MB/sec.

This is an example of the type you need to see any real improvement:

https://eshop.macsales.com/shop/owc-envoy-pro-fx

Look for ones showing as capable of 2800MB/sec transfers or faster or you will lose performance.

2800MB/sec won't be a huge uptick at the user level given your current "on the nominals" speeds but would be good insurance to thwart any upcoming drive failures. Fusion was a faster storage option but, based on toms of posts here, not as reliable and a straight mech drive system or an SSD-only system.

Also, that drive class will still work fine for extra storage on your next computer, Mac or Windows. Retained value.

+1

Third-party AV-ware does nothing but cause problems.

Apple Platform Security - Apple Support

1) Uninstall the TotalAV that you installed on 9-1-25 as per the developers directions.

https://help.totalav.com/__/tech/av/setup/-/av-setup-how-to-uninstall-av

2) Startup in Safe Mode followed by a normal Restart.

Start up your Mac in safe mode - Apple Support

3) Run and post a new EtreCheckPro report.

Thanks for the last EtreCheck report, it shows that Total AV is now gone which is good news. At this point just use the computer for several days and see how it operates. If the problems continue please let us know.

low-life-clothing wrote:

yeah it does feel more responsive and quicker now, many thanks.

Good work, you're welcome.

I guess if I have the potential of a hard drive failure I could get an external drive that I could use as a startup disk, maybe this is worth me doing.

Yes, you can use an external SSD as the startup disk.

There is an excellent User Tip written by Jack-19 just for that.

see > Use an external SSD as your startup disk … - Apple Community

Using an external high quality high speed SSD as your startup drive would be wise. However, that being said you should begin planning on replacing the computer as it will be classed obsolete within a few weeks with the release of Mac OS 26. It will be obsolete because it cannot run OS 26, it is simply too old. This means the time has come assuming you want a fast, reliable and up-to-date machine to begin planning to replace the computer. Many are moving to the Mac mini which is a great buy and out performs the current iMac line.

If you plan on getting an external SSD I strongly recommend visiting www.macsales.com, they offer quite a few which would work okay with your system and give you more time with it if that is the direction you are going.

Looks good.

Is it running better after using Safe Mode..?

You're welcome.