I have a wifi router which was attached with my modem, and the pc was connected to the wifi router through an ethernet cable. Yesterday I moved my modem and router to another room and connected my PC with wifi through an external wifi usb dongle (tp-link tl-w722n). I noticed that the file transfer speed from my cell to PC via wifi is greatly affected. I am not clear why is this happening because although PC is now connected through wifi but the dongle supports more than 54Mbps which is still enough.