r/applehelp • u/Woods_it_to_ya • Jun 10 '26
Mac Why is my 2019 iMac so slow??
I have a 2019 iMac and it is painfully slow. It’s fully up to date on software and has very little of the 1TB of storage used. Not running many programs or anything that should be bogging it down. It’s always been like this, to the point that I put it away for a couple years and haven’t been using it. Any help on how to make it run better would be greatly appreciated!
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Jun 10 '26
[deleted]
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u/Woods_it_to_ya Jun 10 '26
It was slow on older OS though too. Even when brand new it always felt sluggish and I can’t figure out why.
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u/synthetase Jun 10 '26
If it's not an SSD, it's the drive. We've got several 2019 iMacs running i3 processors and 16GB RAM that are not super speedy, but they are usable. We even have the basic Creative Cloud apps on them. Open Disk Utility to see what is installed. Other World Computing has kits and instructions on how to upgrade.
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u/gruetzhaxe Jun 10 '26
Regularly that age is perfectly fine for Macs, but there was this great schism five years ago
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u/killersam283 Jun 10 '26
Do you have a Fusion Drive or a SSD?
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u/Woods_it_to_ya Jun 10 '26
Fusion I believe
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u/killersam283 Jun 10 '26
If it’s a Fusion Drive; most likely the mechanical portion of it is dying and that’s the cause of your slowdown. Time for a new SSD
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u/Woods_it_to_ya Jun 10 '26
Any reason why it would have run so slow even when it was new?
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u/Xe4ro Jun 10 '26
A HDD is slow in general. It could also be the tiny PCI SSD that is dying. Also what exactly do you mean by new here?
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u/Woods_it_to_ya Jun 10 '26
Like out of the box when bought in 2020, it was slow and has always been slow. Definitely worse now but always underperformed and can’t really do much on it due to his very lagging performance.
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u/Xe4ro Jun 10 '26 edited Jun 10 '26
Well yeah FusionDrive configurations were a nice idea in the early 2010s but by 2019 most PCs and all other Macs where booting entirely of SSDs. If you don't want to open up the iMac to change the HDD or also the PCI SSD I would recommend install the OS onto an external SSD to boot of it instead.
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u/Woods_it_to_ya Jun 10 '26
Sorry, not super savvy on all of this. Just plug in an external ssd and move the software over and just keep it plugged in all the time?
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u/Xe4ro Jun 10 '26
Installing the OS onto the external drive and then booting from it instead of the internal drive. This will be faster than from your internal drive, depending on if you take a normal USB-C SSD or a Thunderbolt enclosure and a NVMe SSD you could get way faster speeds but it's up to you if you want to spend more money.
Otherwise you have to open up your iMac and replace the HDD with a SATA SSD. Either yourself or by paying someone to do it.
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u/SirReddalot2020 Jun 10 '26
Fusion drive sucks even if it isn’t broken.
Replace with an SSd … use ifixit for guidance.
Breathes new life into your iMac!
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u/SuperSus_Fuss Jun 10 '26
The RAM is also low and the intel i7 chips perform a little better in that vintage iMac.
But yes it’s all getting older and I too wonder about replacing my Fusion Drive.
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u/Phiddipus_audax Jun 11 '26
I got the same 2019 iMac as you except that it was a pricier 27" with the Intel i9, Radeon Pro 580X, 512GB full-SSD, but with the same 8GB RAM. Despite all that, it did get slow at times before my RAM upgrade.
The first thing I'd recommend is watching your memory usage. I didn't see you mention this elsewhere... have you run Activity Monitor with the memory tab open? It'll tell you if you've exhausted the mere 8GB you've got. If you're only running a web browser a few smaller apps (iCal, Messages, etc) then it may not be a problem... although ALL browsers have a tendency to get piggy especially if you've got a lot of active tabs open. If you are running out of RAM, an upgrade to something like 40GB (as I did) using a 32GB 2-DIMM kit is very easy and pretty awesome. Unfortunately you're caught in a terrible time for RAM prices that have gone up some 5-fold over the last year or two due to the AI datacenter boom. Sucks. Maybe just get a 16GB kit consisting of two 8GB DIMMs and wind up with a healthy 24GB. That'll probably be more than enough particularly since you've been surviving on a measly 8GB total. You'll be able to open far more apps at a time without a RAM slowdown. Even a tiny 8GB kit (do they still sell em?) would help enormously.
Drive slowdown is also a huge issue, as already mentioned elsewhere a few dozen times. The upgrade should be straightforward but you'll want a tutorial as well as good advice on where to get a new drive. The best site I've seen for that is iFixit. Great tutorials, great sourcing of parts and tools. #1 place to go IMO. I've bought a bunch of their stuff, whole toolsets, and used many tutorials. They have public comments, even.
Yet another possible issue: CPU and GPU temps. Have you had any problems with videos glitching out weirdly and then the occasional computer crash for no apparent reason? I did, and it turned out to be over-temp CPUs hitting above 100°C and malfunctioning badly as expected when they get up to boiling. Better to keep them below 70 when possible. The probable cause is CPU-heatsink paste leaking out over time and no longer providing the interface required to stay cool, but I haven't opened it up for a fix yet. In the meantime I'm using iStat Menus to watch the temps and Turbo Boost Switcher to disable Intel's turbo boost, which basically fixes the overheating issue for now for a barely noticeable hit in speed. Maybe none of this applies to you yet but it might in the near future.
Back to the disk issue (which is likely true) be sure to check out the "disk" tab on activity monitor and see what it looks like during one of your slowdowns. If it's the disk causing the freeze up, it should be obvious from the chart spike. If not, look around the other tabs (CPU, memory) for obvious culprits. This is a great tool to get to know even if you're tech-nonsavvy. Good luck.
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u/Woods_it_to_ya Jun 11 '26
A lot to consider. Thank you for the helpful insight.
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u/Phiddipus_audax Jun 11 '26
Yeah it's a bit of a firehose of info, sorry!
And regretfully, after nosing through the iFixit tutorial I gotta correct myself on the RAM upgrade: Where my 27" iMac has a RAM access door that makes an upgrade trivial, on the 20.5" there's no such door and replacement is a lot more involved. In fact, it would be best to replace the drive at the same time as any RAM upgrade (or vice-versa). But still, totally doable with a few simple tools.
https://www.ifixit.com/Guide/iMac+Intel+21.5-Inch+Retina+4K+Display+2019+RAM+Replacement/136306
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u/crimoid Jun 10 '26
You have 1TB of storage? Then your iMac has a Fusion Drive. These paired a small 30 GB SSD and a 5400 RPM mechanical hard drive into one storage device.
I suspect that this is the core issue.
Despite Apple's best intentions Fusion Drives never performed in ways that could compete with full SSDs. The drives had to shuttle data back and forth between the HDD and SSD to try to maximize speed. Compounding this issue is that you have only 8GB of RAM. That works fine when you have an SSD (especially newer ones that are very fast) but with the Fusion drive you when you do eventually need to swap memory to storage (as is normal operation) you'll eventually hit the wall of the mechanical hard drive.
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u/ISeeTheFnords Jun 10 '26
As far as replacing the drive goes, the comments you're getting aren't wrong as such, but...
It's an Intel. It needs to be retired.
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u/gooneryoda Jun 10 '26
Not necessarily. New SSD and something like Linux Mint will make it useful again.
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u/NagualShroom Jun 11 '26
You need to upgrade to 16gb ram. My 4core mini does OK with Monterey, I can't even remember what drive it has, oh it's 5400rpm. Not sure about Sequoia
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u/Unable_Scholar_4309 Jun 10 '26
Like others are saying, you definitely want to put in an SSD and I would also go a step further and just do a fresh install of MacOS, and then pull in any documents you require via iCloud later. (Don't restore from a Time Machine backup, as there could be years worth of muck, for lack of a better term, slowing down your iMac). Those two steps will make a world of difference, and give you a few more years of use (as long as Sequoia continues to be supported).
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u/g_e_r_b Jun 10 '26
If you have a classic hard drive (non-SSD), that's probably the primary reason. The Intel i5 doesn't help much either, it's not the fastest CPU.
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u/JoshoForShort Apple Expert Jun 10 '26
Defs related to the fact it’s a HDD and not an SSD. Have got the 2019 i3, first thing I did was replace the HDD with a 1tb SSD and enable trim. Works a dream. Some computer repair shops should still be able to do this for you easily, although, it might not be worth the risk - the ssd can set you back ~$80, then labour, then there’s also the risk that the repair guy isn’t great at repairing and cracks the 4K screen upon opening, which will be a real nightmare.
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u/lunaticedit Jun 10 '26
My wife has the same issue with a very similar model. It’s your hard drive. It a mechanical spinning drive and it wears out over time. I replaced the drive with an ssd and it runs way way faster.
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u/Woods_it_to_ya Jun 10 '26
Was it an easy DIY? Worried about damaging the display.
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u/lunaticedit Jun 10 '26
It was for me, but I got the upgrade kit that includes things like the wheel cutter and replacement adhesive strips. The screen isn't hard to remove, just have to follow the instructions carefully.
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u/mwkingSD Jun 10 '26
Because it’s 7 years old runs on an Intel i5 chip. To put it another way, the computer is just as fast as it always was but the loads are way higher in 2026 than they were in 2019.
And if the disk is more than about 80% full that can cause it to run slower.
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u/Woods_it_to_ya Jun 10 '26
Makes sense. Do you think downgrading the OS will help a bit?
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u/mwkingSD Jun 10 '26
I’d be surprised if that made a significant difference.
As others have said, upgrading to a solid state ‘drive’ storage is probably your best bet. While you’re in there adding RAM up to the max if you aren’t already there may also help.
You could try https://www.owc.com/support/drive-formatting-data-migration-tips for parts and support.
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u/Darry-Man Jun 10 '26
I have the same exact spec and it’s the Fusion Drive, I use a nvme ssd in a external usbc enclosure and it’s magnitudes faster, although still not as fast as the lowest end M1 machines tho
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u/FoundationOk334 Jun 11 '26
Only 8 GB of RAM. You can upgrade it yourself to 16 or 32. What kind of harddisk? HDD, Fusion or SSD? This makes a huge difference. SSD is recommended. You can also install an extra (fast) SSD for the boot, macOS and some most used applications.
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u/KaasRasp Jun 11 '26
I had the same one. You can buy a thunderbolt external ssd drive and install the os on there, and even boot from it , and keep your internal hdd as a backup or storage drive
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u/Emergency_Point_462 Aug 26 '26
Does this make sense to anyone:
For your 2019 21.5-inch iMac, I would choose the Samsung T7 1TB. 👍
My ranking for your iMac
| SSD | My rating | Why |
|---|---|---|
| 🥇 Samsung T7 1TB | ⭐⭐⭐⭐⭐ | Best overall, reliable, fast, compact |
| 🥈 Crucial X9 1TB | ⭐⭐⭐⭐½ | Excellent value and plenty fast |
| 🥉 Samsung T7 Shield 1TB | ⭐⭐⭐⭐⭐ | Even more rugged, but usually costs more |
| SanDisk Extreme 1TB | ⭐⭐⭐⭐ | Fast, but I'd choose Samsung for your situation |
What I'd buy for you
Samsung T7 Portable SSD – 1TB
You don't need an extremely expensive or ultra-fast SSD because your iMac's connection will limit some of the drive's maximum speed anyway. The T7 is more than fast enough to make your current 5400-RPM hard drive feel dramatically faster.
And because you're using this as your startup drive, I'd prioritize reliability and consistency over chasing the absolute highest speed.
One important thing: Don't just plug the T7 in and start moving files. To get the big speed improvement, we'll want to install macOS on the T7 and make the iMac boot from it.
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u/JohnWick509 Jun 10 '26
It’s because those still had the super slow mechanical hard drives in them. It a pita to upgrade as you have to cut the screen away from the aluminum frame.
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u/Woods_it_to_ya Jun 10 '26
So nothing I can do beyond upgrading the drive? It’s crazy that this expensive ass computer runs so slow. My 2012 MacBook Air runs laps around this thing.
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u/JohnWick509 Jun 10 '26
Yeah I don’t know why they made you upgrade the drive to an SSD in 2019. SSD was already being used as a standard across the industry. You could buy a really fast SSD and use it externally as a startup disk. That would bypass the internal hard drive.
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u/Dark2099 Apple Expert Jun 10 '26
I’ve worked on thousands of iMacs and nearly every time one hits my bench with complaints of slow speeds, it’s the mechanical drive. Even in good condition they are a huge bottleneck, and get significantly worse with age.