iM 4,1-14,4 Is 2013 iMac unable to upgrade past Ventura junk?

[Amethyst1]

This may be a situation in which Apple devised a way to prioritize system file access/use to the SSD blade portion (more on that in a sec), and reserved the lesser-accessed files (like personal/user files) to the HDD.

This is what a Fusion Drive is supposed to do. My iMac pairs a 24GB SSD with a 2.5” 5400rpm HDD — not nearly enough SSD space to maintain the zippyness at all times.

 

[B S Magnet]

This is what a Fusion Drive is supposed to do. My iMac pairs a 24GB SSD with a 2.5” 5400rpm HDD — not nearly enough SSD space to maintain the zippyness at all times.

Generally, that’s how I’ve understood the mechanism for the Fusion scheme, but nothing so explicit or having a hard/fast rule around, say, /System, /Library, and /Applications, all living on the SSD portion and everything else, like /Users, on the spinning rust. I had understood the system, being “Fusion-aware”, would sometimes move frequently accessed /Users files to the SSD area, from time to time, and lesser-used system stuff, like the application or utility opened rarely (or never), like Chess.app, to the spinner area.

The hard/fast approach was, incidentally, the manual method I used for maaany years for my early 2011 MBP: with the help of that (invaluable) tutorial, I created a hard link for /Users to live on a second internal HDD, but everything else was on the much smaller SATA SSD.