There isn't much on a SSD that you can troubleshoot, firmware upgrades are rare, unlikely and might require windows as well (although bootcamp could work). In any case, I strongly suggest replacing it at least for a warranty replacement with the same model, and if you can return and switch to a different model. Otherwise, for your issue, I'd assume either an issue with that SSD in hardware or in firmware. I had two BX class drives (although the older BX100 instead of BX500, 500GB and 1TB) and both failed shortly after end of the 3 year warranty. Part of the issue is that SATA SSDs are pretty dead at this point, and due to the SATA limits on performance manufacturers try to put in the cheapest possible components they can get away with, because you wouldn't be able to notice it anyways over SATA. I've had issues with all QLC SSDs I ever used, at the bare minimum I'd do the MX500 although endurance is similarly extremely low. Can you try powering the Mac off when it happens, so that the SSDs lose power? Maybe that fixes it.Īre you sure you have the BX500? It is the mediocre QLC version that has reduced endurancy, performance and 3 instead of 5 years warranty. It's probably some disk rescanning, or power cycling that does it. I am sure the diagnostics isn't doing anything. magically, the problem is gone.Īny ideas? What are Apple Diagnostics doing behind the curtain, that is healing my Mac?

The only thing that (temporarily) fixes the problem is running Apple Diagnostics at boot time.ĭiagnostics run and find no problem at all. SDD SMART status and self-tests: all green lights.Booting into an Ubuntu USB stick: same as above.Booting into Win 10 via Boot Camp partition: the problem is still there (confirmed by running disk benchmarks in Windows, and by the fact that loading Windows take some 10 minutes).Activity Monitor: no suspicious disk activity (no disk activity at all actually).Of course this makes the Mac totally unusable (takes several minutes to open an application, for instance). I've been pretty happy with the upgrade, but I'm bumping into an annoying problem.īasically, every now and then (typically after leaving the Mac sleep for a while), SATA SDD performance drops to unsustainable levels - say, from 400+ MB/s read/write to 4-6 MB/s. internal (32MB?) PCIe NVMe SSD replaced with 2 GBTB PCIe NVMe SSD (Crucial M.2 PCIe 4.0 NVMe)įor the avoidance of doubt, I have not merged the two drives into one Fusion Drive.internal 1TB SATA HDD replaced with 2 GBTB SDD (Crucial BX500 3D NAND).I have a 21.5' 2019 iMac (iMac19,2 Core i5 with Fusion Drive) that was recently upgraded as follows:

Ssd diagnostics