Thanks for the advice for iMac (Retina 4K, 21.5-inch, Late 2015)

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Thanks for the advice for iMac (Retina 4K, 21.5-inch, Late 2015)

Dear Team,

Having the above model - was getting very frustrated about the annoyingly slow speed - there was no such thing as "a quick email check" etc.....NOTHING!!

Anyway, after reading a few posts and queries regarding speed tests and the like, I elected to have my HDD 5400rpm, changed to a SSD, internal fix (1TB) by my local computer shop (UK)... all-in-all, the total cost was about £270...

Thanks to those that asked about slow speeds previously and also to those with the experience to explain the options.... I now have super speedy machine that will keep me going for many a year and is once again a joy to use..

Thanks Muchly :)

Lee

iMac 21.5″, macOS 12.7

Posted on Oct 29, 2025 2:03 AM

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Answer 1

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~Padawan~ Author

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5 points

Nov 3, 2025 3:29 AM in response to ~Padawan~

For accuracy... I have just checked my receipts £270 is incorrect... I paid £230 inc tax for the work. This was the solution to my problem of this old machine that was very "clunky" and a long drag to access i.e. emails and to open an email and read (example)... then while waiting for the email to open opening a web page would make it worse..

I had tried updating software but am on Monterey (latest version available) and had done lots of reboots, restarts and similar..

I read on here that the drive built into this model (HDD 5400 RPM) was installed to provide a cheaper entry to iMAC etc but of course to the occasional home user like myself, was not aware of the limitations that would arise down the line ... (running speeds and accessing fill in a reasonable time).. So essentially one could say that I "fell for the marketing"... !

So, doing my homework by reading on here (the community, initially) and elsewhere - I then chose to take the plunge and have the SSD installed (cost above)... This is the solution to my problem. This iMAC now has no delay issues waiting for (30minutes at one point !!!!!!) for an email to finally and fully open..

@MrHoffman mentions not spending too much ... the price I paid was checked prior and was inline with the going rate and to me seems worthy of the price paid to resolve my speed and running speeds.

If a heavy/semi/professional user I would feel that the user intelligence of "the tech" and "needs" would steer them away from this HDD model in the 1st place... and would pay the price for the better equipment initially.

I just wanted to say thank you to the community to allow several occasions of reviewing lots of questions on a similar theme, allowing me to come to the resolution... appreciated, as I say.

Issue of slow speed and usability being rubbish = 100% fixed by HDD upgrade to internal SSD by a local computer repair shop at market rate without being extorted.

Keep well

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Answer 2

Nov 1, 2025 7:56 PM in response to claus237

claus237 wrote:

"I now have super speedy machine that will keep me going for many year and is once joy to use"

What happened.........................I would like to know Lee...........................

Why? What happened? How to get more speed?

Hard disks are slow. Here is: Why is my hard disk drive iMac so slow? - Apple Community

Which can mean an external (or internal) SSD: Use an external SSD as your startup disk … - Apple Community

And if you’re going to open up a 21.5” iMac for an SSD implant, and only have 8 GB memory, consider having memory installed during the upgrade.

As compared with the 21.5” model, 27” iMac is much easier to add memory: Install memory in an iMac - Apple Support

As for repairing or upgrading the hardware on any Intel iMac, I wouldn’t spend all that much, as macOS 26 (2026) is the last version, and many Intel iMac models aren’t supported on macOS versions rather older than macOS 26.

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Answer 3

Nov 1, 2025 9:15 PM in response to MrHoffman

MrHoffman wrote:

As for repairing or upgrading the hardware on any Intel iMac, I wouldn’t spend all that much, as macOS 26 (2026) is the last version, and many Intel iMac models aren’t supported on macOS versions rather older than macOS 26.

The OP's iMac (Retina 4K, 21.5-inch, Late 2015) cannot run anything later than Monterey.

Monterey is not one of the "most recent three" supported by vendors like Microsoft and Adobe; it fell off that list when Sequoia came out a little over a year ago.

Monterey is enough to run current versions of

The Firefox Web browser (which only requires Catalina) and most other major third-party Web browsers (Brave, Opera, Chrome, Microsoft Edge).
The LibreOffice office suite
The GNU Image Manipulation Program (GIMP)

and some others.

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