USB performance issues - 1.4.2.beta2?

I´m trying the 1.4.2beta2 on a Dell Wyse 5070 (Intel Celeron J4105) and HDD connected on USB3. I´m getting constant speed around 13 Mb/s with large files on different drives while the possible speed should be around 90 Mb/s. It´s the same speed with the new backup-app and also while copying on the files-app.

Does others have the same problem?
What speed get you with usb-connected drives?
What could be the reason - not recognized hardware on the Wyse? Missing drivers on ZimaOS?
What or how can i check on ssh-console?

Thanks for any help!