Advice on upgrading 2019 iMac

Completely agree regarding the Fusion Drive.

Just out of curiosity, I fed the report into ChatGPT to see if it would find anything that I didn't. I hate to admit it did a surprisingly good job.

Here is what it generated. I can't say I disagree with any of it:

===============================================

Thanks for sharing the full EtreCheck report — that gives a really clear picture of where your iMac’s bottlenecks are. Here are my recommendations, grouped by priority:

🔴 Major Issue: Storage

• Problem: The 2019 iMac is running on a Fusion Drive (slow 5400 RPM HDD + tiny 28 GB SSD). That is the single biggest cause of poor performance. Modern macOS and apps are heavily optimized for SSDs, and the spinning hard drive is dragging everything down.
• Fix:
  • The best performance upgrade is to replace the internal Fusion Drive with a full SSD. A 1–2 TB NVMe SSD via Apple Authorized Service Provider would transform performance.
  • Cheaper alternative: boot macOS from a fast external SSD (Thunderbolt 3 or USB 3.1 Gen 2). Samsung T7, Crucial X9 Pro, or SanDisk Extreme are good options. Format as APFS, install macOS fresh, and migrate data.
  • Keep the internal Fusion Drive only for bulk storage if you don’t replace it.

🟠 Other Performance / Reliability Recommendations

1. RAM Pressure

• • You have 16 GB RAM, but swap is at ~10 GB. That means the system is paging memory to disk constantly → slowdowns.
  • If your workload involves heavy multitasking or apps like Affinity/Photoshop, upgrading to 32 GB would help.

1. Background Processes

• • Many launch agents/daemons (Adobe, Dropbox, Synology, Java, Google, Microsoft AutoUpdate, VPN, Zoom). These eat resources.
• Recommendation: Audit login items and background processes. Disable/remove what you don’t use:
  • • Outdated Java plugin → uninstall if not needed.
    • Old Adobe SwitchBoard (2013!) can go.
    • Synology SIMBL agent is old and can cause Finder instability — remove if not actively using.
• Dropbox updater agents duplicate Apple’s built-in iCloud features — consider consolidating.

1. Heavy CPU Usage

• • Processes like backupd, Safari/WebKit, Spotlight (spotlightknowledged), photoanalysisd spike CPU.
  • These often happen when indexing or during Time Machine runs.
• Fixes:
  • • Let Spotlight fully index, then it should calm down.
    • Exclude large external drives from Spotlight if not needed (System Settings > Siri & Spotlight > Privacy).
• If Time Machine is backing up multiple large externals, performance will take a hit — maybe dedicate one fast external drive only for Time Machine.

1. External Drives

• • Several large USB externals (5 TB, 4 TB, 500 GB). One is USB 2.0 (480 Mb/s) — that can slow I/O when accessed.
  • Recommendation: Use only USB 3.0+ drives for active work. Relegate the slow USB 2.0 drive to archive storage.

🟡 Security & Maintenance

• Unsigned / legacy files: Most are OK, but old Java, Canon, and Flip4Mac plugins are obsolete and could be removed.
• Kernel extensions (kexts): Dropbox, Canon, and Silicon Labs drivers won’t be supported forever. Remove if unnecessary.
• Sharing enabled: Printer sharing is on — turn off if not needed (System Settings > Sharing) to reduce security risk.
• Backups: You have both Time Machine and Carbon Copy Cloner — excellent. Just make sure Time Machine isn’t filling your Fusion Drive with local snapshots unnecessarily.

✅ Summary of Best Actions

1. Replace Fusion Drive with SSD (internal or external boot drive). This alone will make the Mac feel like new.
2. Upgrade RAM to 32 GB if budget allows.
3. Trim startup/background apps (remove old Adobe, Synology, Java, Dropbox extras).
4. Manage Spotlight & Time Machine (exclude big externals from Spotlight, possibly dedicate one SSD/HDD just for TM).
5. Clean up old plugins and kexts (Flip4Mac, Java, Canon drivers, etc).

👉 Do you want me to give you step-by-step instructions on how to set up macOS on an external SSD as a boot drive? That’s the single most effective upgrade without opening the iMac.

first, I noticed you have the Fusion Drive option with the 5400 RPM mechanical drive paired with a small 28GB SSD. that combo is known to "not play nice" with modern macOS. the most cost effective way to speed things up is to get an external SSD and run macOS from that. to implement that, please see this very informative user tip: Use an external SSD as your startup disk with your iMac or Mac mini - User Tip.

and you have so many "minor issues", I would caution against moving everything to a new boot drive. I would manually move any data you wish to keep to the new boot drive. and also re-download any apps, and only from the App Store or directly from the developers' website.

joodge wrote:

Many thanks for your response to my request, particularly the inclusion of the link which I found most helpful and instructive.

you're welcome.

I note you say "...the most cost effective way..." of resolving the problem:

apologies, that actually says more about me than it does about you. I'm among the biggest cheapskates on the planet. :)

your response obviously assumes that I am capable of doing all you describe as necessary myself which, I believe, I am having changed drives (hard and ssd) and added RAM in laptops several times but I have never opened up an iMac for internal surgery

in most cases, changing components in an iMac is MUCH more difficult than doing it in a MacBook. if it is something you think that you might be capable of doing, I would visit OWC’s website and have a look at their DIY videos for HDD and SSD replacement.

I can't see much sense in installing a new SSD drive whether internal or external without upping the RAM significantly at the same time.

if upgrading to an SSD, you would see a much larger performance increase vs a RAM upgrade. but if you plan on opening the iMac anyways for an SSD upgrade, then you may as well upgrade the RAM while the iMac is open anyways.

If I say that cost is not a criterion would you say that I should proceed as you have already suggested or I should take it to the nearest Apple Store (a 250 km round trip...) and get it all done internally?

if cost is not a thought, then YES, I would farm it out to a professional. but again, view the DIY videos. from those, you should be able to determine your ability to tackle the operation.

To avoid a session of Q&A, Q&A  and Q&A  

Download the Application Etrecheck  ( External Link ) directly from the Developer.

This is a Diagnostic Tool that makes no changes to the computer.

It makes a coherent and readable inventory of both the Hardware and Software used on the computer 

The application is free or paid for added features. 

The Report will Not Reveal Any Personal Information. 

Post back the Full Report - Share Report >> Copy , then  paste  >>>> using the Additional Text Icon  <<<<

Your iMac cannot run Tahoe 26 but it can run the latest macOS Sequoia 15.7. So the trade off is the following:

You have about 1-2 years left on this Mac before you won't be able to patch it for security updates. You'll be N-2 next fall season. Which is current release minus two versions. When you reach N-3 the level of support is very limited. If there's an extremely bad security exploit, Apple may elect to release and update for N-3 systems but they also might decide not to. You really should stay within N-2 as much as possible. Most businesses run N-1 so as not to be on the bleeding edge. At work we restrict macOS Upgrades by deferring them for 90 days and even then sometimes 6 months (blocking the installer binaries from running) while we wait for bug fixes from Apple but also 3rd parties that have to adapt to Apple's changes, etc.

The question becomes, do you wish to spend the money on fixing this aging iMac by installing an SSD, perhaps paying labor plus the cost of the drive. Only for the iMac to be nearly obsolete in another year. Perhaps it's cheaper and fits in your budget and you'll upgrade to a newer iMac in a year or two.

Or if budget allows, you just bite the bullet and buy a new Mac. This time around, figure out how much storage you need and buy SSD. Apple finally killed off the fusion drive and they no longer sell them. They were a stopgap measure to provide low cost iMacs & eMacs to schools. For years Apple shipped slow spinning rust HDDs then they added the Fusion Drive as a compromise. Many Apple Consultants ended up replacing those Fusion drives due to failures or just being too slow. Now it's all SSD all the way.

I agree with my colleague @KiltedTim regarding move to M Class Silicon machines

For one reason alone

If your plans are to say current visa vie macOS for the foreseeable future

The current release of macOS 26 Tahoe would be the last version of macOS this computer could upgrade to, if it qualifies

Once Apple Releases macOS 27 sometime next year

Only Apple Silicon computers will qualify

Food for thought

refer " macOS Tahoe will be the last release for Intel-based Mac computers. Those systems will continue to receive security updates for 3 years "

If you're not constrained by cost, I'd say don't put the money into upgrading a 2019 iMac at all. Put the money into a new M4 Mac mini or iMac instead.

@ KiltedTim and @jefferythefrog

Great work there, to your both

Unfortunately, Our Host Notification System seems to exclude me from their distribution list for Auto Notifications of new posting

Fortunately, you both were not

🦉

Owl-53 wrote:

@ KiltedTim and @jefferythefrog

Great work there, to your both

TY :)

Unfortunately, Our Host Notification System seems to exclude me from their distribution list for Auto Notifications of new posting

it would be quicker to mention which notifications I've actually received, than to try and list the ones that haven't showed up. (new posts AND first upvotes) I only seen your most recent reply because I checked back here.

jeffreythefrog wrote:

Owl-53 wrote:

@ KiltedTim and @jefferythefrog

Great work there, to your both

TY :)

Unfortunately, Our Host Notification System seems to exclude me from their distribution list for Auto Notifications of new posting

it would be quicker to mention which notifications I've actually received, than to try and list the ones that haven't showed up. (new posts AND first upvotes) I only seen your most recent reply because I checked back here.

To answer you questions

I did not receive a notification for >>

1 - the ⬆️ vote

2 - Nor OPs reply with the Etrecheck Report

3 -Nor your reply

4 - Nor the reply from @KiltedTim

5 - Nor your current reply to which I am replying to

Go figure

jeffreythefrog wrote:

Owl-53 wrote:

@ KiltedTim and @jefferythefrog

Great work there, to your both

TY :)

Unfortunately, Our Host Notification System seems to exclude me from their distribution list for Auto Notifications of new posting

it would be quicker to mention which notifications I've actually received, than to try and list the ones that haven't showed up. (new posts AND first upvotes) I only seen your most recent reply because I checked back here.

To answer you questions

I did not receive a notification for >>

1 - the ⬆️ vote

2 - Nor OPs reply with the Etrecheck Report

3 -Nor your reply

4 - Nor the reply from @KiltedTim

5 - Nor your current reply to which I am replying to

I should mention, this is Not an Isolated Case

Go figure

🦉

joodge wrote:

Yes, fortunate indeed for me. Just for the record I had not received any notifications either but checked back as a matter of course.

Thank you for your interest and reminding me about Etrecheck.

Thank you for the feedback

Sometimes, the System gets overloaded what with iOS and macOS both being released at the same time and same day

Thusly, this hiccup occurs

Once the excitements of the new OSes dies down

I am sure the Notification System will function as expected

You are also welcome for the previous suggestion, Etrecheck application

🦉

Owl-53 wrote:

The current release of macOS 26 Tahoe would be the last version of macOS this computer could upgrade to, if it qualifies

Sequoia is the end of the line for the OP's 21.5" 2019 iMac.

The only Intel-based iMac that is getting Tahoe is the 27" 2020 iMac. There are only three other Intel-based models of any description that are getting Tahoe, whereas all Apple-Silicon-based Macs released to date are.