SOLVED Late 2015 iMac 17,1 having pausing issues

[twr7cx]

Have a Late 2015 iMac 17,1 Retina (fitted with 4 x 4GB RAM and OWC Mercury Electra 6G 500GB SSD < https://www.owcdigital.com/products/electra-6g-ssd >) that is having some lagging/freezing/pausing issues. When conducting simple tasks there is often, but at random, a delay of 20 seconds or a bit longer, in the result. Often the ‘spinning beachball’ accompanies this but not always. For example:
Click to open Safari and nothing happens for 20 seconds, then suddenly appears.
Click to open the Applications window and it opens without the icons having loaded but after 15 seconds they appear.

So far to in attempt to resolve I’ve tried the following:
Check for any Software Updates (none available – macOS Big Sur latest version)
Check for any updates in App Store
Reset SMC
Reset PRAM/NVRAM
Formatted hard drive and fresh installation of macOS Big Sur from Internet Recovery – even with a clean installation with no additional programs or apps it continues to happen.
Conducted Apple Diagnostics over the Internet (Option + D on start up) – no errors found
Run Memtest86 off bootable drive – no errors found

Any ideas on what I could try next?

 

[Nukeban]

As usual, a process of elimination is required.

Best I can think of at the moment would be to copy your entire setup over to an external drive (using SuperDuper or other such software). Then boot from that external drive. If the problems go away that would suggest the hard drive you're currently booting from may be the issue.

If the problems persist on the new drive too, that suggests either OSX or your hardware as the problem. Now that your entire set up is safely backed up on a 2nd drive, you could wipe the original drive clean and install a fresh copy of OSX. If that solves the problem, then OSX seems the leading suspect. If that doesn't solve it, then maybe a hardware issue is to blame.

There may be simpler and easier diagnostic procedures available. I just don't know what they might be for now.

 

[twr7cx]

As usual, a process of elimination is required.

100%, but I wasn't sure what the next steps would be to do so...

Best I can think of at the moment would be to copy your entire setup over to an external drive (using SuperDuper or other such software). Then boot from that external drive.

I believe you are on the money with potential hard drive fault. Based on another sites recommendation I ran EtreCheck Pro which has come back with:

Runtime: 5:02
Performance: Poor

Performance:
System Load: 1.05 (1 min ago) 1.23 (5 min ago) 1.04 (15 min ago)
Nominal I/O speed: 0.76 MB/s
File system: 39.26 seconds
Write speed: 11 MB/s
Read speed: 396 MB/s

Failing hard drive. The computer has a hard drive that appears to be failing.


Time for me to engage OWC in a conversation about testing their SSD and potential warranty claim.

 

[Nukeban]

Based on another sites recommendation I ran EtreCheck Pro which has come back with:

Thanks for the introduction to this tool, appreciate it.

 

[twr7cx]

Set SuperDuper up to clone the hard drive onto an external USB hard drive. Three days it sat there for and achieved nothing. Currently have a fresh Big Sur installation going onto the external hard drive from Internet Recovery.

 

[twr7cx]

It's been a few months now but I've come back to confirm that the problem was resolved by enabling TRIM, contrary to OWC's instructions for their hard drives. For a full run down on how/why, check out:

Late 2015 iMac 17,1 having pausing issues - Apple Community

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