Hi Sylvia,
a BIOS update to the latest version available on the support server was the first thing I have done, but without success. Also using only one DIMM in slot 1 I have tried without success.
Had a phone call with one of your colleagues from the local phone support in Germany yesterday morning and after our discussion his impression was, that it is a hardware deffect. So I will return the board to my local dealer.
Thank you for your support and kind regards
Ralf