It ends up getting really slow 2meg a sec & ends up freezing up. I tried doing all 169ish Gig at once, that never would finish. So I started doing folders well that didn’t work out. The file manager can’t seem to handle it. From drive to drive in the system it is 60isg meg a sec though. The slowness is odd.
most routers aren’t fast at usb ports, so it will very much depend on that i guess.
Read the manual of your router and check what the max supported speed is.