An apparatus relates generally to a microelectronic assembly. In this apparatus, a first substrate and a second substrate each have opposing surfaces. Contact arrangements are disposed on a surface of the first substrate, including: first contacts disposed as a ring to provide a first array of the contact arrangements on such surface; and second contacts disposed interior to the ring of the first contacts to provide a second array of the contact arrangements on the first surface. The first contacts and the second contacts are for interconnection with first microelectronic dies and second microelectronic dies. The second microelectronic dies are disposed below the first microelectronic dies in same a package as the first microelectronic dies. The first microelectronic dies and the second microelectronic dies include at least two ranks thereof for commonly sharing the first contacts and the second contacts among the first microelectronic dies and the second microelectronic dies.