2019 iMac Very Slow

[bzgnyc2]

I think the "easiest" (and cheapest) solution is to use an external SSD. Do you all think this would improve things?

Yes, a clean install onto an NVMe drive in an TB3 (or better) enclosure will improve things dramatically. I would then not use the internal drive pair at all (either leaving it unmounted, all free space, etc). It's dying and not going to get better.

Also, I would defer the Mail and similar issues until after that is done. I would check that they haven't come back as above but it's not worth debuggiing in the current state. For example, it's possible Mail's database has been corrupted given the dying drive but I wouldn't try to do a rebuild on the current drive. Siimilarly, no need to look at uninstalling extra/unneeded software on the system. Just don't reinstall it after the clean install of the OS. Once on the clean install of the OS onto an external SSD, data restored, etc, come back here for any issues that persist.

 

[Fishrrman]

I'll ask one more time:
How much free space remains on the fusion drive?

 

[webbymac]

I'll ask one more time:
How much free space remains on the fusion drive?

Sorry bud, I thought it was clearly displayed in the screenshots.

It's 82% used.

 

[Fishrrman]

"It's 82% used."

What I'd try:
1. Create a CLONED backup using SuperDuper. It's free to download and use for this job. Click this link to get it:

https://shirt-pocket.com/mint/peppe...://shirt-pocket.com/downloads/SuperDuper!.dmg

2. Boot from the cloned backup.

3. Erase the fusion drive -- entirely. After erasing, use disk utility's "first aid" on the fusion drive. Do you get "a good report"? If so, REPEAT THE PROCESS FIVE TIMES in succession. Do you get a good report every time?
If you do, I'll take a GUESS that whatever problems your friend is having aren't "drive-based".
(EDIT: it's possible that the platter-based portion of the fusion drive has become highly-fragmented over time -- if so, erasing and restoring should take care of that)

4. Now "clone back" the contents of the external cloned backup you're booted from.

BUT...
BEFORE YOU DO...

Go through the drive and start throwing stuff out.
You want to get about 30% "free space".

The extra stuff could be "moved off" to another drive for now.

Again, this is what I'd try.
No promises, but it's "a good, clean start-over".

IF EVEN THAT DOESN'T WORK...
... might be time to consider getting an external SSD and setting that up to become the "new boot drive".

You could get a USB3.1 gen2 SSD, which would give read speeds around 920.
I'd suggest the Crucial X9. I've got one of these and it's a "little gem" -- fast and small.

Or... if your friend wants to spend more... get a thunderbolt3 SSD. I can't make a recommendation because I've no experience with them.

 

[webbymac]

Is USB-c 3.2 (the crucial X9 SSD) the same as TB3; I mean can I plug it into that socket?

 

[bzgnyc2]

Is USB-c 3.2 (the crucial X9 SSD) the same as TB3; I mean can I plug it into that socket?

Not the same but should still work for this. If you already have that Crucial X9 SSD available it should be fine for this. If I had to buy a new drive for this, I would get at least a TB4/USB4/TB3/USB3 compatible enclosure/SSD.

Thunderbolt 3 (TB3) has much higher bandwidth than USB 3.x and usually lower overhead by allowing the host access to the NVMe drive in the enclosure almost as if it is internal to the host. And as such more certainty around TRIM and SMART support. However, a good SSD connected via USB 3.2 will still be much faster than any single HDD.

Starting with TB3, Thunderbolt switched to using USB-C for their plugs and ports. Additionally Thunderbolt 3 ports work with USB 3.x devices just llike regular USB ports do. As such, a USB 3.x device with a USB-C connector should plug right into a TB3 port. Then while a pure TB3 device won't work in a pure USB 3.x port, most TB3 devices also have auto-fallback to USB mode. So in theory they should all talk to each other at the mutually highest protocol between them. The higher protocols generally being faster.

Anyway, won't hurt to try a clean install on to the X9 SSD and see if that restores system performance. Biggest downside is potentially having to repeat the data backup/install/data restore later and any time spent moving files around to free up the X9. If it restores performace as expected and no need to go even faster, great you're done. Maybe even until it's time to replace that system with the latest, greatest. Otherwise you can always switch to an external TB3/NVMe or replace the internal drive at a later date to get even more performance.

 

[webbymac]

Ordered the Crucial X9 in 2TB

 

[webbymac]

Well, this is interesting. I haven't installed the X9 SSD yet.

Since starting this thread, I have run some of the disk checks on my own 2011 iMac. It's run flawlessly since I've had it. It has a 256gb SSD and a 1TB HDD. Always been good. I have a backup drive. I've run disk checks on it over the years, but I've never run DriveDX.

So, I ran DriveDX, out of curiosity and it reported that my HDD was all good, but my SSD had errors (see screenshot).

However, then, very soon after, my HDD started clicking. I keep my photos library, and a few other things, on the HDD. I shut down and restarted and the HDD disappeared. I did a PRAM reset and it appeared again and I managed to do another backup.

I then decided to unmount the HDD as it's not required for daily use. Today though, the HDD fans were blowing hard and the HDD has disappeared again from Finder and DiskUtility and it won't remount. All very odd, given that DriveDX reported that it was all good.

 

[Bigwaff]

I then decided to unmount the HDD as it's not required for daily use. Today though, the HDD fans were blowing hard and the HDD has disappeared again from Finder and DiskUtility and it won't remount. All very odd, given that DriveDX reported that it was all good.

Post DriveDX HDD report, if possible.

 

[webbymac]

Post DriveDX HDD report, if possible.

Unfortunately I didn’t save it but it was all good, no errors or faults. I think it was like 92% lifespan, something like that (which seems crazy considering it’s over 10 years old). Nothing to indicate it would fail in the next few days.

 

[bzgnyc2]

Unfortunately I didn’t save it but it was all good, no errors or faults. I think it was like 92% lifespan, something like that (which seems crazy considering it’s over 10 years old). Nothing to indicate it would fail in the next few days.

There may have been no way to predict especially given it was the HDD. DriveDx (and CLI tools like smartctl) just pull the drive's SMART counters and highlight if there is an issue. I understand DriveDx compares drive-specific values against an internally developed database to calibrate/risk-adjust so-to-speak but in any case all that requires that the drive believes it is going bad or at least experiencing errors. It's possible that your HDD experienced a sudden, catastrophic failure of circuitry or mechanical components and the best warning practical was what you experienced.

I like SMART and dislike not being able to read it. However, I generally interpret "good" SMART results as "no known issues" rather than actually good. Kind of like you can't prove something is true only that all known evidence is consistent with something being true. Then it's one protection but by no means full protection against data loss / disruption. It's like backup cameras or similar. Even if it only avoids 50% of accidents it still has value.

 

[webbymac]

Ok, so I cloned the fusion drive to the new SSD yesterday using SuperDuper and all is working well today!

Thanks for all the helpful responses

 

[macnavarra]

Ok, so I cloned the fusion drive to the new SSD yesterday using SuperDuper and all is working well today!

Thanks for all the helpful responses

Full installer Yosemite on fusion drive https://gist.github.com/EmranAhmed/b042e6fc365cdccb8d59 hint! Mac mini (late 2014). Buy a "good to go!" firmwared SSD like... "OWC" connected it via external usb serial ata enclosure use Yosemite disk utility to partition it with Mac OS Extended (Journaled), name it Untitled, select source Apple Fusion and drag the untitled parted SSD to de target context box and voila.... etc.. .