So you have an iMac 2015 or 2017 or even 2019 (or 2013) and for some reason the computer has recently started to slow down. It was working fine for months or years, but for a while it seems like it takes longer to start up, longer to load programs, longer to do everything, and you’ve started to see that now terrifying swirling ball of color that means the system is taking longer than expected to complete it’s task.
Unfortunately, this is not uncommon in these iMacs. I have had many clients contact me to ask if I can help to speed up their iMac, that it has been slowing down for a while, or that it suddenly got slower after installing the latest MacOS. In almost every case, the problem is the hard drive, Apple’s fusion drive. This drive is actually two drives: an SSD for the system and core applications, and a mechanical hard drive for everything else. Back in 2012/2011 when Apple introduced this drive, it was an interesting concept that allowed for the operating system and programs to run off the faster (and MUCH more expensive) SSD technology, while data, etc. could be stored on the slower, much larger, and (and MUCH cheaper) HDD technology. The problem is the HDD portion hasn’t aged well, and SSDs don’t last forever either.
These drives slow down over time and especially after a number of upgrades. My experience has been that the drives in the iMac 2013, iMac 2015 and iMac 2017 do not do well past High Sierra. I have had clients running fine on High Sierra, then they’ve had sever slowdowns after upgrading to Mojave, but especially when going past that to Catalina, Big Sur or Monterey. This happens even though Apple will gladly encourage you to upgrade your system to these later versions. As Metallica said, “Sad but true”.
So, what can you do about it? It is possible to install an internal SSD and replace the fusion drive, but there is a risk of cracking the display when trying to pry it off the very strong adhesive. A better option is to transfer the system to an external SSD. Depending on which iMac you have – and thus which Thunderbolt port technology you have – you can achieve improvements in speed of 10x or greater. I think that’s pretty good.
The process is straightfoward, and the MacOS has very good support for moving your startup disk from the internal drive to an external SSD. Here’s how you do it: https://discussions.apple.com/docs/DOC-250003583.
Not comfortable doing that? Contact us and we can do it for you.