u/Best-Commercial1543

Hey everyone,

My iMac 27-inch 2017 has suddenly become painfully slow and I’m trying to figure out what’s going on.

About 3 years ago I replaced the original drive with an SSD, and honestly the machine felt amazing after that. No issues at all until recently.

Now it does something weird:

• It boots up fine
• First few minutes are normal
• Then it slowly starts crawling
• Finder gets laggy
• Apps take forever to open
• Beachballs everywhere

I already tried reinstalling macOS from scratch, thinking it was software related, but the problem stayed exactly the same.

At this point I’m wondering if:

• the SSD could be dying,
• it’s overheating/throttling,
• maybe a bad SATA cable or thermal sensor,
• or even RAM issues.

What confuses me is that it always starts fine, then gets worse after a little while.

Has anyone here seen this before on a 2017 iMac?