My iMac's running slow and I want to re-install Catalina
Please help me solve the problem.
This is a report from EtreCheck.
My Mac is slow and reboots with a black window of death about a problem.
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Before your post got moved, I read your EtreCheck report and spotted the root issue. The move trashed the report so you may wish to repost it.
Three things point to a solution:
- Your iMac has an after-market SSD.
- TRIMForce is NOT enabled on the SSD
- Your "Read" speeds are normal but your "Write" speeds are horribly slow., about 1/20th of your Reads. That ain't good.
And I know why. I found through personal experience that TRIM must be enabled on aftermarket SATA SSDs. When first installed they are fast, but the Writes start to slow after some use to the point where the computer is almost unusable. Mine took about 2 years after SSD initial install to show the speed loss yours shows.
That is corrected first by enabling TRIMForce, followed by some easy maintenance steps. No disassembly involved.
1) Before doing anything else, BACK UP the drive to an external device
2) READ this article by an SSD vendor on how to enable trim: How to Execute ‘Trimforce’ Command with Your SSD
3) Make it so.
Now the maintenance. To get TRIM to do its job, you need to do several Safe Mode boots. Not just the usual quickies; you must let the computer "soak" in Safe Mode for up to an hour at a time. Don't try using the computer while it is thinking.
After a soak, restart normally and run EtreCheck again. Look at the drive scores under "Performance." The aftermarket SATA SSD in my Mac does this years after the catastrophic drop in drive performance responded to my enabling "TRIM"
Performance:
System Load: 1.61 (1 min ago) 1.60 (5 min ago) 2.94 (15 min ago)
Nominal I/O speed: 0.15 MB/s
File system: 28.20 seconds
Write speed: 487 MB/s
Read speed: 482 MB/s
The hardest part of this is not messing with the computer while it soaks in Safe Mode.
FYI; Best practice when posting a question here is "always start your own new thread." When you tag onto another's question, it makes the thread hard for us volunteers to work and dilutes the attenint the original poster deserves. Starting a new thread gets you 100% of our attention. Thanks!
