TotalAV

Only people who want their 21st century Macs to run like it was 1991,

Remove it. NO anti-virus is needed or appropriate. You paid Apple a shed-load of money to include automatic protection and maintenance routines into macOS. This started 20 years ago and today's Mac OS is a very robust system.

The reason you get a performance penalty is that this third-party dungware conflicts with what Apple built into the system.

For the same reason, you should install not third-party "cleaning/tune-up" apps. They are totally unneeded.

Do not fall for fear marketing!

There is no reason to ever install or run any 3rd party "cleaning", "optimizing", "speed-up", anti-virus or security apps on your Mac.  This user tip describes what you need to know and do to protect your Mac: Effective defenses against malware and other threats - Apple Community   

Uninstall the TotalAV software according to the developer's instructions. When done you can check to see if you've removed all of the supporting files by downloading and running Find Any File to search for any files with the application's name  and the developer's name in the file name.  You'd do the following search: 

1 - Name contains totalav

Any files that are found can be dragged from the search results window to the Desktop or Trash bin in the Dock for deletion.

FAF can search areas that Spotlight can't like invisible folders, system folders and packages.  

Uninstall your 3rd party anti virus app. It is not needed, uses system resources while providing no benefit, and it may cause problems.

You said you are running TotalAV, that is a third party anti virus app. Now you are saying you ran Disk Cleaner, another unnecessary third party app that may contribute to problems.

I've yet to see any AV App lately that their uninstaller removed all the cruft.

EtreCheck is a FREE simple little diagnostic tool to display the important details of your system configuration and allow you to copy that information to the Clipboard. It is meant to be used with Apple Support Communities to help people help you with your Mac. It will not display any personal info.

https://www.etrecheck.com/

Pastebin is a good place to paste the whole report if you capture the URL while there…

https://pastebin.com/

Whew, they've changed pastebin & made it harder, but after pasting in, click Create new paste button, then Embed button, then copy the URL...

<script src="https://pastebin.com/embed_js/KuvnghqA"></script>

The important part is...

https://pastebin.com/embed_js/KuvnghqA

Workable but harder for me to work with...the Note tool on the bottom of this editor's toolbar, as shown in the image, to copy and paste the output from EtreCheck. In a Reply before you click post, look for this to add longer texts...

I can relate something I've seen here easily 20+ times involving notebook Macs. They are fitting for this discussion because battery runtime reflects system workload. An iMac can have the same issue; it just isn't as apparent on something plugged to the mains.

People were reporting ~2 hour run-times on Mac notebooks new enough to run 6-8 hours or more on one charge. In EVERY case, at least one anti-virus or so-called "cleaning" app was installed. Removing the fearware returned battery runtimes to normal. That is a huge affect on performance.

I was a Tech coordinator for the school I worked at in the '90s. We had one virus that attacked our machines then.

Oh yeah. We had a few Macs at work and a new hire fresh out of Uni brought a floppy of "fun Mac stuff." It was full of malware. However like your example, it was in the 90's and I recall the newest Mac affected was running OS 6.0.7!

The real built-in defense that includes automatic cleaning and maintenance came in with mac OS 10 in 2000. Since then the system, without hurting performance, runs automated scripts daily, weekly, and monthly. They do everything those third-party "cleaners" and "optimizers" claim to do. After 20 years of the industry knowing that the Mac, cat-like, cleans itself, those selling cleaning software appear to me to be committing fraud. One man's opinion.

ljcline59 wrote:

Perhaps I should just delete TotalAV. Thanks.

I think I said that.