Abstract: The present invention is a cost effective module that provides high performance, high density and highly reliability interconnections needed between the various circuit devices that form a functional system or a part of a larger system. It includes circuit members having high speed, impedance-controlled transmission line signal paths, short land grid array interconnections between circuit members and, optionally, driver line terminators built into one of the circuit members, for maintaining high electrical performance. Suitable applications include mainframe computers, workstations, telecommunications networks, or other electronic equipment. The circuit members may be formed on conventional printed circuit cards with unpacked or packed circuit devices attached directly to the circuit members. Thermal control structures may be included to maintain the circuit devices within a reliable range of operating temperatures. A clamp is also included.