There seems some debate

In answer to all the annoying gimboids who say that mv deletes files as it goes, even if copying across drives or file systems – no, it doesn’t. At least, not on my system. It copies, then deletes. Which is a frigging pain in the arse because my system is 99% full, so there’s insufficient space for it to do that.

Then it falls over.

Which is the best outcome so far. Given the Gigabyte board’s general unreliability, it’s either that or it reboots randomly in the middle of doing it.

Either of which is a bucket of cack.