New WD My Book 8TB extremely slow - Anyone know how to fix it

Just got the WD My Book 8TB (2x 4TB Red Drives), set up as RAID 1 and connected to PC via USB-C.
The drive is really slow at doing anything, I have several older versions that contain Green drives and use USB 2 and Firewire 800, these transfer files much quicker.
I have tried using different cables (I have multiple USB-C and USB-A 3 cables) and also tried attaching to my laptop.

Anyone experiencing the same issue and found a fix?

Hi,

You could refer to the following link: Backup: Common Causes and Solutions of Slow Backups