Hello guys,
so after I managed that my 4TB My Cloud is working again I plugged in my 3TB My Book:

Well unfortunately the connected USB 3 device is very slow… It takes hours until it displays the content of a folder
Copying files is okay but it takes a few minutes after this has finnished
the data rate is about 30MB/s
When I plug the device directly into my PC everything is fine.
On my My Cloud it does not take time for calculation or something it starts immediatly with writing the data with a constant rate. The writing rate rate is about 36MB/s and reading about 60MB/s… I am not quite happy with that because it should be faster or not?
On my PC I have a SSD there I have a writing rate of about 450MB/s.
Cheers
Alex