Really slow Passport Elements USB3.0 1TB

Recently  bought a Passport Ultra 2TB and used for the first time Smartware (i used to do my backups manually…).
Once the backup was complete, my older external disk, a Passport Elements, was formatted just like the new one and i performed the same backup procedure, but this time it took roughly more than 24 hours (for +/-800gb). I dont recall if this disk was always this slow as i´ve always did small incremental backups to it over 3 years, i´ve never backed a high amount of data at once.

Finding this really odd, i´ve run some benchmarks on both disks, with the same usb cable and port. Both drives firmware is up to date, as well the usb controller drivers. 

Here are the benchmarks:

And here is the Passport Elements on a usb2.0 port… 

Any ideas?? Faulty disk?

Hello,

Try running a diagnostic using WD DLG.

Data Lifeguard Diagnostic for Window

Did the extended test, the disk passed.