I have two identical, new, WDC WD30EZRX-00DC0B0 external, self-powered 3TB USB drives connected to each of 2 of what are supposed to be the USB 3.0 ports on my Gigabyte Technology GA-78LMT-USB3 motherboard. My system is running Linux Slackware version 13.37.0, kernel 126.96.36.199.
Copying from one drive to another seems very, very slow. It takes about 8 hours to copy a 190G file.
On the port closest to the mother board, initial command line pathname completion takes 20+ seconds. ls -ltr initiall takes 25+ seconds. likewise, df takes 15-ish seconds to return
On the port above that one pathname completion and ls are instantaneous.
By contrast it only took 4 hours to copy over 400GB to an identical USB drive on another computer (although not copying between USB drives).
Does 8 hrs for 190GB this seem reasonable for copying between USB drives?
Should both drives not be plugged into the same bus?
Does this seem like a problem with motherboard, drive?