The use of higher electromagnetic carrier frequencies for communication in a computing results in both increased spatial information density and larger available modulation bandwidth. However, assuming that the communication energies are dissipated, the heat that must be removed from unit volume per unit time increases quickly with higher frequencies, resulting in a maximum useful frequency based on our limited ability to remove heat. We show that this frequency is relatively insensitive to system specific parameters and estimate its order of magnitude to lie near the infrared and visible bands of the spectrum. © 1992.