To use the ethernet port, you must install the drivers provided with the installation CD or download them to the manufacturer's website. There are no speed loss in use.
I tested the product with an amplifier (powered by USB and sound card serves me), a cooling plate (3 fans) and a hard drive (USB powered). All devices are normally powered and work perfectly (driver installation of the almost instantaneous amplifier). The hard drive has a writing speed of about 30 to 35MB / s (on average), which is absolutely correct and corresponds to a throughput of USB 3.0
I recommend this product to any user (especially laptops) that lacks USB port, there is no slowdown. I also recommend this USB Hub as ethernet to USB adapter for two uses: on netbook with only the WiFi but also on the smartphone / tablet with USB OTG technology, I tested and it works!
Little extra of manufacturer: 6 months guaranteed available for product registration, for a total of 1 year and a half!