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SSD reading data non-stop after sleep

Since replacing my fusion drive for a SSD on my late 2017 iMac, I've had an issue where after sleep the disk reads around 60mb/s nonstop. Only read, no write. And it never stops. When this happens MacOs is quite slow and I'm worried that the SSD might wear off. Hundreds of gigs of data end up being read for no reason.


I've tried reinstalling mac os completely, wiped out everything and installed the most recent mac os version. This has not solved the problem. I've had this problem since at least 3 macos versions.


When I reboot macos, things are fine. Only when I let the computer idle for some time does this happen, and once this happens it never stops unless I reboot. I tried disabling any kind of sleep but it still occurs.


I've searched the web everywhere, haven't found any solution. Any help would be greatly appreciated. Thanks!

Posted on Nov 19, 2023 9:22 AM

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19 replies

Nov 19, 2023 9:57 AM in response to blink666

Thanks for that information!


The Crucial BX500 SSD itself is the issue. The BX-series of SSDs from Crucial are generally lower-quality, slow, and unreliable. After they've been online for a while, they can be as slow as a hard disk.


To fix this issue, I'd recommend you setup a high-quality, external SSD. Using an external SSD doesn't require opening the Mac again, which Apple didn't design for end-users to do. Plus, with an external SSD, you can continue to use it as external storage when you get a new Mac.


To get started, this user tip should help: Use an external SSD as your startup disk … - Apple Community.


If the SSD I recommend in the user tip appears out-of-stock at the Apple Store, these SSDs are also great options:


The Envoy Pro FX is a Thunderbolt SSD, and can reach very high speeds of around ~2.6GB/s. The Elektron is a USB SSD, and can reach speeds of around ~950MB/s. In either case, both are faster than an internal SATA SSD which can only reach ~500MB/s.


-Jack

Nov 19, 2023 11:29 AM in response to blink666

If that is so, why does it work flawlessly when I'm on windows?


Which operating system has more files? Which are you booted into more frequently? Which has more intensive workflows? If it's macOS, then that partition of the drive is being taxed more heavily than the Windows side.


You cannot use an external SSD with Bootcamp. Perhaps you can keep using Windows from the internal SSD, then use the newer external SSD for macOS.


-Jack

Nov 19, 2023 10:10 AM in response to supercondr

Well that's the thing, I should've mentioned it in the post, I can't see anything corresponding to this much data in activity monitor. When I got 200 gigs read the most "bytes read" I see are a couple of gigs.


The samsung drive is a USB flash drive... yes I need it to work on windows for work. But the issue is 100% unrelated.


Edit: it just happened now as I let my mac go idle for 15 mins... as you can see, can't see anything in activity monitor:

Nov 19, 2023 9:56 AM in response to blink666

Run activity monitor from Applications/Utilities directory.


look for what application is doing all the disc read/writes. Select the Disk tab, this will report all apps using the disk. I suspect its photo and or media analysis.


Was the reason for formatting the Samsung drive in exfat so you could share with windows? If not, I might try and make a backup and then reformat the drive an Apple format. Restore backup after.

Nov 19, 2023 10:11 AM in response to Jack-19

Interesting that an external SSD could work, actually got an unused NVMA drive in my office. The speed would indeed be better.


That being said, the crucial disk itself is working great, my issue seems more software-related. if my mac doesn't go idle, the issue never happens. I also use bootcamp and am never having this issue on the windows side.

SSD reading data non-stop after sleep

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