To solve the problems associated with heat generation as packaging density increases, especially with the use of VSLI devices, high density metal core PCBs have been developed. The manufacturing process is evaluated alongside that of conventional G‐10 boards, as are the electrical properties of the two types. Characteristic impedance and propagation delay figures are compared; back crosstalk and heat dissipation capability are investigated, the incorporation of the metal core being found to produce a considerable improvement in terms of heat conductivity.