iMac 2017 27": Optimal Mac OS Version?

[Jodeo]

I'm about to list for sale my 27" iMac 2017 5K running on a 3.8GHz i5 (Intel); model MNED2LL/A (18,3). It has 40GB RAM and a 2TB Fusion drive.

Currently has Mojave 10.14.6 and it crawls; tempted to install an older OS before selling so buyer can have a faster machine.

Should I bother changing the OS?
And if so, which Mac OS would be good?

Thanks.

 

[BrianBaughn]

Very unlikely that someone is going to buy that and use it with the hard drive that's in there…which is what is making it slow. They'll install some sort of an SSD.

I wouldn't bother worrying about the version of macOS.

 

[Juicy Box]

You could defuse the fusion drive, and just explain you split the Fusion Drive and it now has a 128 GB solid-state drive for the OD and an aging 2 TB HDD for additional storage.

The 128 GB solid-state drive is probably still pretty fast.

 

[appltech]

The biggest obstacle is that Fusion Drive, or its replacement to an SSD drive.
As above mentioned you can try to split the disk using the CoreStorage commands (to disable and split the disk so SSD for the system and main data and HDD -- for the rest)

According to your Mac model -- Big Sur or Monterey

 

[gilby101]

I'm about to list for sale my 27" iMac 2017 5K running on a 3.8GHz i5 (Intel); model MNED2LL/A (18,3). It has 40GB RAM and a 2TB Fusion drive.

I don't agree with the comments above. The 2TB Fusion Drive has 128GB SSD and should be fine for most usage. Just remove from Apple ID, etc. and then erase the disk and install latest supported macOS (macOS 13.5) before selling.

 

[Juicy Box]

I don't agree with the comments above. The 2TB Fusion Drive has 128GB SSD and should be fine for most usage. Just remove from Apple ID, etc. and then erase the disk and install latest supported macOS (macOS 13.5) before selling.

Maybe you missed this from the OP:

Currently has Mojave 10.14.6 and it crawls;

APFS doesn’t work well with HDDs, and based off of what I have seen, this has only gotten worse with each new OS version.

With there now being 6 years on that HDD, I bet it’s age is impacting performance as well.

 

[gilby101]

APFS doesn’t work well with HDDs, and based off of what I have seen, this has only gotten worse with each new OS version.

The Fusion layer between APFS and the physical drive would make a significant difference here.

With there now being 6 years on that HDD, I bet it’s age is impacting performance as well.

My experience with HDD is that they either work or they don't. Not a gradual physical degradation.

 

[Juicy Box]

My experience with HDD is that they either work or they don't. Not a gradual physical degradation.

That is the exact opposite of my experience with failing HDDs.

I currently have six Macs that had or still have failing HDDs, and most often, it is a slow process with symptoms appearing sometimes years before they fully fail.

Are you sure you didn't mean SSDs? Because SSDs on the other hand don't usually have much warning. They work, and they they don't. Often times, you cannot see them on Disk Utility after they go black.

Edit: actually, I just remember about the failing HDD that I still occasionally externally use that was in my Late 2011 17" MBP (replaced it with a SSD), and also my 2006 Mac Pro 1,1 that I have had for almost 17 years, and I have had a few HDD failures on that one as well with the same symptoms. They would be be eight Macs current at my home with these failing HDD symptoms.

 

[zevrix]

I'm about to list for sale my 27" iMac 2017 5K running on a 3.8GHz i5 (Intel); model MNED2LL/A (18,3). It has 40GB RAM and a 2TB Fusion drive.

Currently has Mojave 10.14.6 and it crawls; tempted to install an older OS before selling so buyer can have a faster machine.

I sold a similar iMac last year (also 40 GB but i7, the rest seems to be identical).

I installed a clean latest Monterey. A clean system usually runs relatively fast for an average user.

I myself only used the internal Fusion drive for Time Machine. My system was installed on an external SSD, and all work files were on external drives. To me, running macOS from a non-SSD drive is too slow.

The person who eventually bought this Mac didn't even want to try it: just gave me the money, put the boxed iMac into his trunk and left. Ha.