Hi,
sorry for warming up an old thread, but i do have exactly the same problem.
It took me ages to even find out that it was the extension cable but i am pretty sure.
My motherboard:
AsRock H77-PRO4-MVP Intel H77 1155/4xDDR3/SATA3/USB3/HDMI/DVI/Glan/RAID ATX
Front AND Back USB ports are...