A circuit chip mounting arrangement for use in a multiple chip unit (MCU) of a computer is disclosed which provides high chip packing density to decrease signal path lengths and thereby increase operational frequency. Chip mounting assemblies are employed which include a centrally located metal heat sink block attached to a chip site on the MCU base. A plurality of circuit chips are attached by their top sides to the front and back sides of the heat sink block with a thermally conductive electrically insulating adhesive. The chips are electrically connected to vertically disposed interconnect boards on either side of the heat sink block, and corresponding flex circuits are employed to connect the interconnect boards to bonding pads on the chip site. A pair of the chip assemblies can be disposed on a single chip site of the MCU, and any desired number of circuit chips can be disposed in each chip assembly.