W510 high standby consumption when USB mouse tongle attached

Dear All,

since I had to recover my W510 tablet due to a system crash do I experiecnce a problem which did not occur before: The standby consumption increases significantly (battery loses more than 1%/h) when my logitech wireless mouse dongle is attached in the USB port of the docking station. I tried it with a 2nd mouse dongle: same effect. Also switching of the mouse does not help. When I attach an USB memory stick instead the consumption is not increased.

I already searched in the Windows 8 energy options and in the bios but did not find something i could parametrize to switch of USB at standby or so. Drivers are thee newest available at acer.com.