SEVERE performance issues (Imac unusable)

Get a backup, if you don’t already have one.

Remove MalwareBytes, and remove CleanMyMac, per the vendors’ instructions, restart, and check again. The built-in anti-malware does just fine, is way less chatty, and the built-in maintenance does well, too.

Otherwise and failing that, please download and run (free) EtreCheck, and when the run completes share the report to the clipboard. Then open a new reply here, and press the additional-text button that looks like a printed page to get a text input box big enough to paste the hardware and software configuration report here, and paste and post that report here.

If performance is still bad, I’d also have a chat with the repair place that swapped the Fusion for an SSD.

At this juncture, I would not purchase an Intel Mac.

DeputyDawg wrote:

I don't see a way to attach a document

Use the Additional Text button to attach your EtreCheck report:

But to be honest, there probably isn't too much you can do. Sometimes those Fusion drives are just horribly slow. You won't notice it until you start using swap space in virtual memory. That can overwhelm the SSD and start using hard drive space. The computer will stop dead in its tracks at that point. You'll need to restart to recover.

Some things you can do:

1) Limit your OS upgrades. Looks like it's too late for that. Newer operating systems are designed for Apple Silicon computers, which are 10-100 time faster than the one you have. The fastest operating system for that computer is the one it shipped with. Newer ones will only be slower.

2) Limit your 3rd party system modifications. These kinds of modifications are extremely popular. This technical support forum would be ghost town without them. They are literally what keeps the lights on around here. Use at your peril.

3) 3rd party "security" and "privacy" apps are the worst. There are no "threats". The closest analogy to Mac malware is UFOs.

4) The system is designed to run at its best with default settings. There are absolutely zero changes you can make that will improve performance. Any change, any software installation, will come at some cost to performance. For most people, with a fast, modern computer, they usually don't notice anything. But you're already right on the edge. It's very easy to push that old computer over the performance cliff.

5) Do NOT buy another similar computer. Just take the cash and light it on fire instead. At least you'll get some warmth from that.

6) I don't know what you mean about a Mac mini being in the 3+K range. With a name like "DeputyDawg", I assume you're in the US. A new Mac mini with a 1 TB hard drive would be $999. A 27" display equivalent to the iMac would be $200. That computer would be at least 10 times as fast, if not more. Or get a MacBook Air with a built-in display for about the same.

7) You don't need 4 TB of startup drive storage. If you really did need that, then you wouldn't be balking at the $3k price for it. You don't need to match the specs with the old computer. The new one will be unbelievably faster. You just have to avoid shooting yourself in the foot with a tiny hard drive. A popular online suggestion is to buy a Mac with a tiny hard drive and use an external drive for booting. That is a malicious suggestion. Don't do it. While you do need at least 1 TB, you don't need 4 TB on the startup drive. If you need more storage for infrequently used files, then get an external SSD. Stop wasting your time with that NAS junk.

DeputyDawg wrote:

Thanks, I have the full Etrecheck report but I am not home. I will provide later.

I hate to sound dumb, but I did not know Apple had their own anti virus. I will look into that.

Apple XProtect is built in, automatic, and it and the rest of macOS security work in ways that the add-ons cannot. It’s also blocked efforts by add-ons that have tried to clobber parts of macOS; defenses against third-party false positives. The built-in cleaning also works well.

I was thinking along the same line as reaching out to the repair center. I checked my credit card. The work was done Jan 30th.

I’d still want to look at the hardware and software configuration report here. It’s possible this is the SSD, but I’ve also met add-on security and cleaning apps and other issues that can degrade performance.