Super slow mac but no CPU hogs!

[iHavequestions]

My mac is super slow and its not caused by anything I can see in the activity finder as there's no CPU hogging programs.

I get the spinning color wheel anytime I click anything. It doesn't matter if it's something core to the basic functions such as opening a menu or even just opening the Activity Monitor itself took forever. My computer should be well powered enough so this doesn't happen.

I have a 2017 iMac with 4.2 Ghz, 64GB of memory. Running Catalina 10.15.7

What can I try?

 

[iHavequestions]

I can't even restart because it hangs. I walked away for an hour and a half and nothing happens. Had to do a hard reboot with the button. But when I boot back up, similar problem. I know I can reboot in safe mode. But then what can I do?

 

[BrianBaughn]

Fusion drive still in there?

 

[iHavequestions]

Fusion drive still in there?

Yes, but thats always been the case.

 

[Fishrrman]

What SIZE is the fusion drive?

Suggestion:
Attach a USB3 SSD (any size), put a copy of the OS on it, and try booting that way.
Any difference?

 

[Honza1]

My own prior cases with this symptom turned out to be disk errors or disk full. Check free space and boot in recovery and run Disk utility. Do you have backup? You may need it. If you do not have backup, time to make one (it will be slow...).

 

[ssmed]

My guess would be disk problems or disk full.
The other things to watch are large dropbox synchronisations as these are a real slowdown