A multi-package integrated circuit assembly can include a first electronic package having a first package substrate including a first die side and a first interface side. A first die can be electrically coupled to the first die side. A second electronic package can include a second package substrate having a second die side and a second interface side. A second die can be electrically coupled to the second die side. A conductive interconnect can be electrically coupled from the interface side of the first package substrate to the interface side of the second package substrate. A collective substrate can be attached to the first electronic package. For instance, the collective substrate can be located on a face of the first electronic package opposing the first package substrate. The collective substrate is electrically coupled to the first die and the second die through the first package substrate.