imac slowness hard drive or something else?

I’m having issues accessing the EtreCheck report, probably due to an ASC bug. I presently can’t see the report, but will try another path to access it and its data.

In addition to checking for a split Fusion drive, run the hardware diagnostics and see if those report any errors.

If this is an 8 GB Fusion configuration, that’s not going to be able to write lots of data to storage quickly.

If the Fusion has been split and you’re using just the HDD, it’ll be glacial. The low-end iMac 8 GB configurations are good for FaceTime and mail and casual web browsing and Photos and such, but are not going to be good at running games. Too little memory, and the storage can’t keep up with apps—such as games—that can require a lot of memory or can require writing lots of data to storage quickly. Or both.

Fusion is a way to make a hard disk drive less slow, using a small—but far faster—SSD. The SSD tries to handle the most critical data and tries to act as a fast cache for writing data to the hard disk, but macOS has to shuffle files from and to the SSD as the apps running change their access patterns. macOS doesn’t always guess what needs to be cached correctly, and writing a lot of data to the SSD will eventually stall as that data still has to be copied to the hard disk. And in modern computers, storage is used to extend the amount of memory available, but slowly. Memory is very, very fast. Storage is not nearly as fast. So if 8 GB is filled, some part of that 8 GB has ro be offloaded to storage. When those memory contents are needed again by an app, the contents must be read back into memory from storage, possibly evicting other memory out to storage.

SSD main storage is vastly faster than hard disk storage, and SSD can compensate (somewhat) for too-little main memory. For gaming, I would usually want at least 16 GB and potentially more, and an SSD.

Not knowing the exact 2015 sub-model nor what graphics processor is installed, it is hard to say. Slow loading is a common complaint that is a hard drive issue but you have Fusion drive that should be faster. Some entry Level iMacs have a dual-core processors instead on the better quad-core CPUs. and some have less-capable integrated graphics instead of game-friendly discrete graphics.

To avoid our playing a really boring game of "20 Questions" with you and delaying a resolution, a good place to dispaly machine specs and start looking for culprits is with a snapshot of your software configuration. Fortunately there is a safe, secure way to do that. 

We can quickly and within the confines of these forums help you determine if software issues are the problem if you use EtreCheck, available free from the Mac App Store here:

https://itunes.apple.com/us/app/etrecheck/id1423715984?mt=12

We can also see hard data about drive performance and RAM usage. Etrecheck is the development of a long-serving and trusted contributor here expressly for displaying information in these forums to help us help you. It will not reveal any personal or secure information.

Run it, select “Report" from the left-hand pane (scroll down to the bottom of that pane to find):

When its report displays, click the "Share Report" icon from EtreCheck’s toolbar and then "Copy report” from the resulting dropdown.

⚠️ Please DO NOT highlight the text in the report before using Etrecheck’s “Copy report” command—that will garble the formatting and make the report slower and harder to evaluate.

NOTE: Changes in late 2018 to the forum software require you use the “Additional Text" icon (see example below) to embed the report into a post:

Paste the report into the resulting “Additional Text” window:

Sorry to be slow getting back. A chance to see the grandkids yesterday outweighed checking in here!

Your report did not display properly in Safari so I had to used another browser. I do not see any big software conflicts or known troublemaker apps. However you bought a computer with 8GB of non-upgradeable RAM to run Adobe CC. That can make CC sluggish.

As for MineCraft, this computer has entry-level integrated graphics instead of the more powerful discrete graphics later 4K iMacs have. That may be what you son is fighting,

The big issue is your drive performance::

Performance:

System Load: 3.25 (1 min ago) 2.80 (5 min ago) 2.13 (15 min ago)

Nominal I/O speed: 0.74 MB/s

File system: 24.32 seconds

Write speed: 144 MB/s

Read speed: 201 MB/s

Those scores are low for a Fusion drive. I collect EtreCheck drive scores and that is roughly 1/3rd of the speed a healthy Fusion should do. Even worse, the scores are only marginally better than scores I have for a 2011 iMac with a purely mechanical 7200rpm, 6GBps drive, the fastest of the rotational drives for consumers.

I do not use a Fusion drive but it could be that the drive has "split." meaning either that it forgets that it is hybrid drive and is not properly integrating its SSD and mechanical component functionss. Or it could be that in using Disk Utility to move things to the SSD, they were split.

How to fix a split Fusion Drive - Apple Support

As I admit to being lacking in Fusion expertise, I will send out a call for additional assistance from some of the senior contributors with Fusion drive experience. All my stuff is SSD.

That Fusion looks okay: disk1s2 [APFS Fusion Drive] 1000.00 GB

The APFS-formatted contents of disk2 are built on the Fusion.

What gets presented to the user is: disk2s4 - VM (APFS) [APFS VM] (Shared - 4.30 GB used)

Usually easier to explain a working Fusion drive from the storage report labeling rather than the EtreCheck, FWIW. (There might be a display-related enhancement to EtreCheck lurking here, too. Not that I’m fond of Fusion drives, but they work, and can offer a whole lot of capacity for cheap. Just not good performance, if you’re at all familiar with the performance of a not-trash-grade or TRIM-less SSD.)

Too little memory, slow graphics, slow storage, not a gaming machine.

If the diagnostics don’t show hardware issues, the options for improvement are limited to attaching an SSD, but that won’t fix the (lack of) memory nor improve the performance of the Intel Iris Graphics.

Try posting an attachment with the report here. You might end up posting it on a different server, and it might be accessible to me.

It looks like your Fusion Drive is Ok. You can launch the Terminal app and run the following command:

diskutil  list  >  ~/Desktop/drive-info.txt

This command will list all the drives (and I think the Fusion Drive as well) and save the information to a text file on the Desktop called "drive-info.txt". This will make it easy for you to post the output here using the "Additional Text" icon which looks like a piece of paper. It would be best to disconnect all external drives first to limit the information displayed so it is easier for us to check on things.

Check the health of the SSD & Hard Drive by running DriveDx and posting the report for each drive here using the "Additional Text" icon which looks like a piece of paper.

You may also want to check the health of your external drive, however, that will require installing a special USB driver so that DriveDX can communicate with the USB drive. Not all USB drive controllers support the necessary communication to allow DriveDx to access the drive's health information.

You may want to see how your iMac runs without the external drive connected.

Other processes 45.15 % (?)

Open Activity Monitor & sort on CPU%, can you se what processes might be using that 45.15%?

OWC does well with SSD external storage options for Mac.

For best speed, you’ll want a connection using Thunderbolt 3, Thunderbolt 2, USB 3.1 gen 2, or USB 3.1 gen 1 (aka USB 3.0) in decreasing order of performance.

Too little memory, slow graphics, less-slow storage, this is still not a gaming machine.

You’ve fixed the only reasonable option, the rest is in-built.

Post the EtreCheck anew, but I’m not hopeful past whatever few days rebuilding caches and indexes might happen with a new macOs install.

Hey! Sorry this is dragging out. I'm having the Devils own time sharing your Etrecheck report with others. I can only read it in FireFox and the formatting is weird. Not you--it appears to be yet another forum bug.

Another helper suggested you do "About this Mac..." and select the "Storage" tab:

Ignore any external drives for now. Do you see one or two internal drives listed? If only one labeled "Fusion Drive" where my example reads "Flash Storage," that indicates a proper Fusion drive--not split.

I will send the "About this Mac" Storage info. Should I attach it as a screenshot?

Not necessary, just tell us if it shows one internal drive or two. That's easier.

Also, it sounds like the fusion drive is a pretty poor performer...

Some do really well, like this result from my collection:

  Write speed: 379 MB/s

  Read speed: 1027 MB/s

That's why i was wondering about your drive's status.

maybe at some point I can buy a new imac with better specs?

Hopefully, and with an Apple SSD. I have s 2017 iMac 5K with Apple's factory SSD. Its read/write scores look "OK.":

    Write speed:  2156 MB/s

    Read speed:  2863 MB/s

I have a fairly busy Saturday going on but later today I'll jot down the bits I would get were I doing the external SSD option. That should get you drives scores of about 400MB/sec.

A$X wrote:

I tried entering the command but got no reply. Are the spaces intentional? Is the red text of the word info important? Is it all one line? Sorry for the newb questions. This is what I entered exactly including the spaces:

diskutil list > ~/Desktop/drive-info.txt

There should be no question about copy and paste the command line from above.

You can always see the output directly in the Terminal window, simply copy and paste:

diskutil list internal

You have the slowest stock computer Apple sells, a SSD will drastically improve performance, as recommended above.

iMac 21.5” tends to be a bit of a hassle to open.

Since it’s a desktop with a fixed-location, adding and using external storage is less of an impediment than with mobile.

Going from Fusion to SSD is fewer pieces, and a performance upgrade, but not otherwise significant.

Yes, the internal storage bus has a (theoretical) peak of 6 Gbps, though actual performance will be lower.

I was able to copy the Drive info from the report in FireFox:

Drives:

disk0 - APPLE SSD AP0032H 24.00 GB (Solid State - TRIM: Yes)

Internal PCI-Express 5.0 GT/s x4 NVM Express

disk0s1 - EFI [EFI] 315 MB

disk0s2 [APFS Fusion Drive] 23.69 GB

disk2 [APFS Virtual drive] 1.02 TB (Shared by 5 volumes)

disk2s1 - Macintosh HD - Data (APFS) [APFS Virtual drive] (Shared - 252.11 GB used)

disk2s2 - Preboot (APFS) [APFS Preboot] (Shared)

disk2s3 - Recovery (APFS) [Recovery] (Shared)

disk2s4 - VM (APFS) [APFS VM] (Shared - 4.30 GB used)

disk2s5 - Macintosh HD (APFS) (Shared - 11.15 GB used)

disk1 - APPLE HDD HTS541010A9E662 1.00 TB (Mechanical - 5400 RPM)

Internal SATA 3 Gigabit Serial ATA

disk1s1 - EFI (MS-DOS FAT32) [EFI] 210 MB

disk1s2 [APFS Fusion Drive] 1000.00 GB

disk2 [APFS Virtual drive] 1.02 TB (Shared by 5 volumes)

disk2s1 - Macintosh HD - Data (APFS) [APFS Virtual drive] (Shared - 252.11 GB used)

disk2s2 - Preboot (APFS) [APFS Preboot] (Shared)

disk2s3 - Recovery (APFS) [Recovery] (Shared)

disk2s4 - VM (APFS) [APFS VM] (Shared - 4.30 GB used)

disk2s5 - Macintosh HD (APFS) (Shared - 11.15 GB used)

disk3 - WD My Passport 0820 2.00 TB

External USB 5 Gbit/s USB

disk3s1 - EFI (MS-DOS FAT32) [EFI] 210 MB

disk3s2 - M*********t (Mac OS Extended (Case-sensitive, Journaled)) 2.00 TB (722.26 GB used)

Mounted Volumes:

disk2s1 - Macintosh HD - Data [APFS Virtual drive]

1.02 TB (Shared - 252.11 GB used, 764.27 GB available, 750.99 GB free)

APFS

Mount point: /System/Volumes/Data

disk2s4 - VM [APFS VM]

1.02 TB (Shared - 4.30 GB used, 750.99 GB free)

APFS

Mount point: /private/var/vm

disk2s5 - Macintosh HD

1.02 TB (Shared - 11.15 GB used, 764.27 GB available, 750.99 GB free)

APFS

Mount point: /

Read-only: Yes

disk3s2 - M*********t

2.00 TB (722.26 GB used, 1.28 TB free)

Mac OS Extended (Case-sensitive, Journaled)

Mount point: /Volumes/M*********t

I cannot move the entire report from Firefox to Safari. Keeps posting as a web link.