Why is USB 3.0 4-port hub so much faster than direct connection from laptop to external hard drive?

[mike_mgoblue]

QUESTION: Why is my USB 3.0 4-port hub so much faster than the direct connection from the USB 3.0 port of the laptop to the 8GB external hard drive?

When I use a direct connection between my laptop computer, which has a 750GB 5400rpm hard drive, and my 8GB WD easystore external hard drive, the transfer rates are actually much slower than when I use a USB hub. For example, I recently copied and pasted four movies adding up to about 120GB of data. Here is what happened.

1. First, I copied the four movies adding up to 120GB of data on my laptop hard drive, and then pasted them onto the one 8GB external hard drive. It took about 80 minutes to transfer, because the data transfer rate was only about 30mbs. The data transfer rate had spikes that ranged from 20mbs to 35mbs.

2. Second, I then connected the other 8GB external hard drive that is the exact same model. This time I used the 4-port USB 3.0 hub. This time the data transfer rate was much faster - at times over 90mbs. The data transfer rate had spikes ranging between 50mbs to over 90mbs. It took only 30 minutes to transfer the data.


3. Third, as an experiment, I connected both of the 8GB external hard drives at the same time via the USB 3.0 hub. I copied all four movies with the 120GB of data from one hard drive to the other. This time the transfer was even faster than ever. The data transfer rate was about 150mbs, and there were no spikes at all in the transfer rate. It was a steady line of 150mbs the entire time.


I have done experiments with other large data transfers. For some reason, the direct USB 3.0 connection to an external hard drive is much slower than when a USB 3.0 hub is involved. ... Does anyone know why this is?

[T'hain Esh Kelch]

Is there an external power supply for the USB hub?