I've recently bought a new rig and plan on getting into 4K editing. Unfortunatelly, I haven't invested the time before buying to optimize the disk setup and ended up with 6 following disks:
2x Samsung SSD 960 EVO (NVM Express)
2x Samsung SSD 860 EVO (Sata)
2x 4TB WD (Storage)
I've tried to figure out myself how to set them up (Previews, Scratch disk, Auto Save, Media, etc.) but guess I'm failing somehow since the times to load, preview and just scrub through the footage is laggy and just makes the editing experience almost untolerable.
I've got I9-7900x CPU, Nvidia GTX 1080 and 32 GIG-s of RAM (guess thats the low end..) so I figured I shouldn't have much troubles scrubbing through the footage..