A computing device includes a sealed computer chassis housing, a heat source, a heat spreader, and a thermal pad. The sealed computer chassis housing, defines an interior space and an exterior surface with a heat sink for the interior space. The heat source is disposed within the interior space. The heat spreader includes a plurality of thermally-conductive protrusions coupled to one or more components of the heat source by an intermediate thermally conductive layer. The thermal pad is positioned above and in thermal contact with the heat spreader. The thermal pad is positioned to contact an interior wall of the sealed computer chassis housing opposite to the heat sink.