UR 824 randomly disconnected

Hi everybody i bought a Steinberg Ur 824 a couple of months ago. It was working good with cubase and ableton but sometimes it disconnected for a couple of seconds and reconnected again. In last Months it do it frequently.
What i did:

  1. I’ ve thought it was drivers problems but i did a disinstallation and installation drivers from zero. I had windows 7 pro so i thought it was a OS problem and i put windows 10 pro, SAME ISSUE

  2. i try to change Usb from 3.0 to 2.0 better but SAME ISSUE

  3. i bought a Hub 3.0 with 5 volt and i put the interface there but SAME ISSUE

  4. I had a PciE with other Usb i thought it was a problems about to much current from motherboard to Usb ports i remove it SAME ISSUE

5)I change the Usb Cable SAME ISSUE

  1. i disable the other audio drivers “Realtek audio etc etc” SAME ISSUE

  2. i disable usb power sleep SAME ISSUE

  3. I used the UR with my laptop it seem work …

Any suggestion?

My Pc:

Asrock Z97 Extreme 3
CPU: Intel Core i7-4970k
Corsair Vengeance LP DD3 1600 C10 4X8GB

I ve bought a PCI and i put my interface there, finally it works perfectly, what could be the problem? motherboard faulty?