Hi,
As you saw, other user reported this situation through the community, most of then were able to find a solution for the transfer speeds.
Please see if the following links helps.
http://community.wd.com/t5/WD-My-Cloud/Gigabit-router-still-slow-transfer-speed/m-p/627073#M1966
http://community.wd.com/t5/WD-My-Cloud/Slow-Transfer-to-3TB-MyCloud/m-p/812531#M23253