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iMac 2017 21.5" painfully slow (etrecheck report included)

My iMac has become incredibly slow. Reading other threads on here, it appears someone might be able to look at the etrecheck report and let me know if I need a new computer or if there is a solution that will make it less like wading through treacle ....! Thank you in advance :)


iMac (2017 – 2020)

Posted on Jun 25, 2023 10:52 AM

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Question marked as Top-ranking reply

Posted on Jun 25, 2023 11:49 AM

Welcome! Posting the Etrecheck report was the right thing to do. Problems identified in one post. Well played!


I see two issues, one of which ku4hx has already spotted.


First this:


Hardware Information:

iMac (21.5-inch, 2017)

Status: Supported

iMac Model: iMac18,1

2.3 GHz Dual-Core Intel Core i5 (i5-7360U) CPU: 2-core


This is the crippled educational/institutional iMac made to be atractively priced for bulk buyers. It has a laptop-class 2.4GHz 2-core processor. The standard consumer model that year, the 21.5-inch 4K, had a proper desktop-class four-core processor, the SLOWEST of which ran at 3.0 Ghz. The performance penalty with the edu-model was massiv. These are benchmark scores for your iMac v. the consumer 21.5" in 2017:



OK, you can't change that now. However, the second problem, the slow factory mechanical hard drive problem, is at least addressable. It is possible to make what you have work better for you.


Your drive performance:


Performance:

System Load: 1.93 (1 min ago) 1.85 (5 min ago) 1.83 (15 min ago)

Nominal I/O usage: 0.11 MB/s

File system: 42.52 seconds

Write speed: 80 MB/s

Read speed: 71 MB/s


Those scores are first-rate for that drive model, but are still dreadfully slow for todays apps and OS version. The fastest mech-only drive system score I have on record are still under are under 200MB/sec.


Modern iMac with solid-state drives (SSD) run over 2000MB/sec. My 2017 5k with factory SSD:


Performance:

    System Load: 1.66 (1 min ago) 1.42 (5 min ago) 1.31 (15 min ago)

    Nominal I/O speed: 0.23 MB/s

    File system: 20.35 seconds

    Write speed:  2156 MB/s

    Read speed:  2863 MB/s


Apple Silicon Macs are now breaking the 3000MB/sec barrier.


The cost-effective fix that does not involve a new computer is to get an external USB3 drive containing an SATA 6GB solid-state drive. When set as the boot volume, it can do 400MB/sec and that is very noticeable in use. See this excellent user-submitted tip on how to do it.:


https://discussions.apple.com/docs/DOC-250003583


Depending on the size of the SSD, this can be done at home for under US$100.


Please post back if needed.


Allan









11 replies
Question marked as Top-ranking reply

Jun 25, 2023 11:49 AM in response to elaine_stecks

Welcome! Posting the Etrecheck report was the right thing to do. Problems identified in one post. Well played!


I see two issues, one of which ku4hx has already spotted.


First this:


Hardware Information:

iMac (21.5-inch, 2017)

Status: Supported

iMac Model: iMac18,1

2.3 GHz Dual-Core Intel Core i5 (i5-7360U) CPU: 2-core


This is the crippled educational/institutional iMac made to be atractively priced for bulk buyers. It has a laptop-class 2.4GHz 2-core processor. The standard consumer model that year, the 21.5-inch 4K, had a proper desktop-class four-core processor, the SLOWEST of which ran at 3.0 Ghz. The performance penalty with the edu-model was massiv. These are benchmark scores for your iMac v. the consumer 21.5" in 2017:



OK, you can't change that now. However, the second problem, the slow factory mechanical hard drive problem, is at least addressable. It is possible to make what you have work better for you.


Your drive performance:


Performance:

System Load: 1.93 (1 min ago) 1.85 (5 min ago) 1.83 (15 min ago)

Nominal I/O usage: 0.11 MB/s

File system: 42.52 seconds

Write speed: 80 MB/s

Read speed: 71 MB/s


Those scores are first-rate for that drive model, but are still dreadfully slow for todays apps and OS version. The fastest mech-only drive system score I have on record are still under are under 200MB/sec.


Modern iMac with solid-state drives (SSD) run over 2000MB/sec. My 2017 5k with factory SSD:


Performance:

    System Load: 1.66 (1 min ago) 1.42 (5 min ago) 1.31 (15 min ago)

    Nominal I/O speed: 0.23 MB/s

    File system: 20.35 seconds

    Write speed:  2156 MB/s

    Read speed:  2863 MB/s


Apple Silicon Macs are now breaking the 3000MB/sec barrier.


The cost-effective fix that does not involve a new computer is to get an external USB3 drive containing an SATA 6GB solid-state drive. When set as the boot volume, it can do 400MB/sec and that is very noticeable in use. See this excellent user-submitted tip on how to do it.:


https://discussions.apple.com/docs/DOC-250003583


Depending on the size of the SSD, this can be done at home for under US$100.


Please post back if needed.


Allan









Jun 25, 2023 11:51 AM in response to elaine_stecks

As ku4hx said the primary problem is that you purchased the slowest Mac that Apple offered at the time of purchase: 8 GB of RAM and a 5400 rpm boot drive.


You can increase the disk access speed to 450 or more by getting the right external SSD, cloning your boot drive to it with Carbon Copy Cloner and running from it.


I recommend you contact Customer Support at OWC (MacSales.com) and get their recommendation for the fastest external SSD for your iMac model and budget. They are considered the premier 3rd party hardware supplier for Macs. I'm just a very satisfied customer of theirs with a number of their external SSD.


Also it's helpful if you reboot frequently as that clears out temporary system and application cache and swap files and will help with system performance.


Jun 25, 2023 12:03 PM in response to Allan Jones

Hi Allan,

Thank you so much for the detailed reply.

That all makes sense now you've explained it and pointed out the relevant bits.

I'll give the home fix a go adding the external drive as you've suggested - hopefully there are beginner instructions out there! I really don't do complicated things with my iMac, but it has been driving me crazy how slow it goes!


iMac 2017 21.5" painfully slow (etrecheck report included)

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