Hello Yuji,
Thanks for contacting Plugable!
There are many different factors that can affect USB performance, including:
- USB driver on your computer
- USB device attached to switch
- does your USB device require more power than available over USB bus power
- total USB cable length from USB device to your computer
- type of data that you are transmitting
- total size of data transfer
- how storage medium (hard drive, USB drive, etc) is formatted
- is the hard drive healthy or failing
- are there any encrypted files
As you can see, there are many different reasons why you may be experiencing these performance issues. For best performance, we recommend that you direct connect your USB device directly to your computer to see if there is any improvement.
Thank you,
Jordan
Plugable Technologies