I did a partial reinstall of Fedora 30 on my XPS13 as I completely failed at migrating it to UEFI from legacy.
Such a weird problem - after a bios update only half the RAM was visible to the OS in legacy mode. I tested with various liveCDs and figured out it was fine in EFI mode so decided to switch it over.
I'd initally assumed it was a RAM module prpblem but it was nothing of the sort. So strange.