I have a mid-2010 iMac that I haven't used for a while. I wiped the disk and installed High Sierra (10.13.6). I don't remember the previous release of MacOS it was running with. It has a 3.2GHz i3, 1T HDD and 12G of RAM.

It's incredibly sluggish, clicking or typing will often result in the spinning wheel for a few seconds before anything happens. I've installed nothing on it beyond what High Sierra does by default.

My intention for this Mac is to use is for web browsing, writing, watching videos and music creation (with Garageband or other DAW).I have no intention of changing the HDD to an SSD - I don't think it's worth the cost and I have 2019 iMac that I have access to. This is just a secondary computer I'd like to have in my house.

Would an older release of MacOS fix this sluggishness? What release of MacOS would you recommend?

  • Why don’t you wan’t to change the drive? For $50ish you can get a 256GB SSD. That vintage iMac had the glass that was held on by magnets and the LCD with torx screws - it’s super easy to open and change the drive. For a rather small investment, you can make it perform better than new.
    – Allan
    Aug 13, 2020 at 4:17
  • 1
    From everything I've found, it's not at all super easy to change the drive. This one, for example says, "it should be clear that upgrading the storage in these models is rather challenging."
    – DDx
    Aug 13, 2020 at 4:50
  • It’s not as hard as they make it out to be: see ifixit.com/Guide/…. They say “moderate”, but that s due to the LCD. if you take care with that component and go slow, , everything else is easy. I did 2012 iMac and that used glue on the display. upgraded the drive and it ran faster and cooler
    – Allan
    Aug 13, 2020 at 5:43
  • That's the 21" model. For the 27", it's "difficult". But thanks for looking that up.
    – DDx
    Aug 13, 2020 at 16:23
  • It's the exact same process. Obviously, I can't make you do anything, but I would give it a go. They say "difficult" because the LCD is larger and more unwieldy, but that's someone's subjective opinion of it. Once you have the LCD removed, which is the hardest part of the job..you're home free.
    – Allan
    Aug 13, 2020 at 16:46

2 Answers 2


I would plug in an external SSD - those machines continue to run as fast at work as they were the day we purchased them with one exception: storage degradation

  • Fusion drives are likely done with fast writes unless you have it powered off got 8 of the 10 years it served you.
  • HDD at 10 years are just going to need an erase and probably retirement, anyhow.

Get an SSD or external drive over thunderbolt or FireWire and install the newest OS it can run. Then migrate all apps, settings, data you care to get off the internal drive and then erase the internal drive so you don't see it as a drive on the desktop is my advice.

  • Thunderbolt didn't appear on iMacs until 2014. I'm limited to FireWire and USB 2.0 external drives. But this is likely the easiest solution for upgrading the drive.
    – DDx
    Aug 13, 2020 at 5:30
  • @DDx Excellent! Added that as FW is also superior to USB for this era hardware.
    – bmike
    Aug 13, 2020 at 22:37

I have the 27" Mid-2010 iMac with High Sierra. Mine is sluggish as well but not as bad as you say yours is. My internal Fusion drive is dying and that, I believe, is why mine is so sluggish. I've had High Sierra for a long time and never experienced a problem with it. It ran fine until my drive started failing. Since you still have your original drive you may want to check its status. I use Drive DX to get the SMART status of my drives.

You may want to run EtreCheck Pro which will tell you if your machine is sluggish and possible causes and solutions. EtreCheck Pro on my machine tells me its too sluggish to be caused by software and it's probably due to a failing drive.

  • Both DriveDX and EtreCheck are showing my drive is failing. So, definitely need a replacement drive, probably doing the easier external.
    – DDx
    Aug 13, 2020 at 16:25

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .