trs96
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I support many iMacs at work that are dated from about 2011 to 2013. They all came with either a 500 GB or 1TB mechanical HDD as the boot drive. It's always a good idea to upgrade them to Mojave (2012 or newer iMacs) and a new SSD. (opening one up is not a simple process though) The 2011s don't have Mojave support. We stop at High Sierra with those. All these models of iMac are already painfully slow when booting from the HDD and the conversion to APFS makes them even slower in my experience. I've always wondered how much slower they get after APFS conversion. I just saw this article on the CCC website by Mike. He has written an in depth analysis of why the new file system causes Macs with a HDD startup disk to get even slower. Very interesting read on this topic.
Mike says: The article is fairly technical, here are the key takeaways:
This second video (Do It Yourself) gives you all the info on what you'll need for the SSD upgrade in a 27" iMac. OWC doesn't show that.
The downside of this DIY video is that he says nothing about electrostatic precautions. He's on carpeting when working on the SSD upgrade. Not a good idea. Note that the smaller 21.5" iMacs already use a 2.5" HDD so don't buy the third party SSD adapter as shown for the 27" model in the video. The suction cups are really helpful. If you were to drop the glass it can do some real damage. Just look at the LTT video on Youtube where they drop the glass on a brand new iMac.
Finally, here's a video by a technician that is in real time. He's upgrading the 21.5" iMac to a new SSD. This is a well done video that explains some of the risks of doing this procedure.
Mike says: The article is fairly technical, here are the key takeaways:
- Enumerating an APFS filesystem on a traditional HDD (rotational disk) will take 3-20X longer than HFS+ on the same hardware.
- This performance difference is most noticeable on a macOS startup disk that is (or includes) a rotational disk.
- If Apple doesn't make some concessions in the APFS filesystem to accommodate the slower seek performance of HDD devices, then a rotational device will never be able to provide acceptable performance as a production macOS startup disk.
This second video (Do It Yourself) gives you all the info on what you'll need for the SSD upgrade in a 27" iMac. OWC doesn't show that.
The downside of this DIY video is that he says nothing about electrostatic precautions. He's on carpeting when working on the SSD upgrade. Not a good idea. Note that the smaller 21.5" iMacs already use a 2.5" HDD so don't buy the third party SSD adapter as shown for the 27" model in the video. The suction cups are really helpful. If you were to drop the glass it can do some real damage. Just look at the LTT video on Youtube where they drop the glass on a brand new iMac.
Finally, here's a video by a technician that is in real time. He's upgrading the 21.5" iMac to a new SSD. This is a well done video that explains some of the risks of doing this procedure.
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