Re: Errore - "HWC2005: System board Riser cable or interconnect failure. Check connection." on new R520.

If your server has this riser:

DXX7K Riser 1- X16 Slot (Used in 2P Config).  

Then it will throw the error, since its looking for the 2nd CPU. .  Will your server go past the error and run?

Regards,