The dongle works fine to charge and use USB devices. I cannot tell for sure, but it does seem to charge much slower when I have 4 devices plugged into a USB powered hub. When I tested my AC powered USB hub, it seemed to charge at a normal rate (probably because it wasn't relying on the USB port for power). I plugged in this then plugged in a DisplayPort device for a second screen, which had it's own hub built in for mouse, keyboard and external drive. This basically turned my tablet into a full workstation. This little device is AMAZING!