Hello..
I have an M4800 (Specs attached - along with config.plist.Hope that's enough?).
I have two SSD internal drives - one with Catalina, one with elCapitan (as a fallback). Both work fine (couple of things e.g. sleep missing, display luminance, but nothing fatal).
In the Optical Drive Bay I have a caddy holding a 3rd drive (for Data storage).
The thing is…
el Capitan handles any drive installed in that Bay perfectly normally - good speed in and out.
But Catalina reads any of those same drives in it really really slow - slow to recognise folders and files and really slow to open and save them - beachball spinning for ages…
I'm wondering if anyone knows if there's anything I could try to solve this?
(Of course, curing Sleep would be a welcome bonus)!
M4800 Sys Specs and Config.zip