A semiconductor package assembly includes a first semiconductor package. The first semiconductor package includes a first body having a first device-attach surface and a first bump-attach surface opposite to the first device-attach surface. A second semiconductor package is bonded to the first device-attach surface of the first semiconductor package. The second package includes a second body having a second device-attach surface and a second bump-attach surface opposite to the second device-attach surface. A dynamic random access memory (DRAM) device is mounted on the second device-attach surface. A decoupling capacitor is mounted on the second device-attach surface. Conductive structures are disposed on the second bump-attach surface of the second package, connecting to the first bump-attach surface of the first body of the first semiconductor package.