what is disclosed is an apparatus for determining the cooling characteristics of a cooling device used for transferring heat from an electronic device . the apparatus comprising a cooling device thermally coupled to a heat pipe . the heat pipe having an exposed surface for the selective application of heat thereon . a localized heat source is selectively applied to at least one region of the exposed surface . the heat source preferably capable of being varied both positionally relative to the exposed surface and in heat intensity . a heat shield is preferably positioned around the exposed surface of the heat pipe to isolate the operational cooling device from the localized heat source . a temperature detector repeatedly measures a temperature distribution across the exposed surface while the cooling device is in a heat transfer mode . the temperature distribution is then used to thermally characterize the cooling device .