finally I achieved communication between SDR console and my Ettus x310 (by going back to the old UHD Firmware 3.15) .
Initially SDR console crashed after flashing when I started SDRconsole using the 1G connection (I assume default BW was set too high for the connection)
Using the fiber connection I can get SDR console to start and see some signals going through the x310.
Unlikely as with the USRP200, it seems I have no control in SDR console to adjust gain, bandwith or Antenna port settings of the UBX160 daughterboard. (running last beta software)
Any change of available parameters take a long time. Load on the 10G fiber connection is given as 13,5% - so this is indeed too high for the 1G networkcable.
Apparently there are a few Ettus x310 users here - May I ask you, what daughterboard(s) do you have fitted.