An article of manufacture comprising a heat sink to be attached a heat source, being coupled thermally and directly for conductive flow of heat from the heat source to the heat sink. The heat sink is formed via extrusion of material of suitable density and mass to absorb heat from the heat source based on design requirements. The extruded heat sink is configured with specially oriented extruded fins and machined cross cuts to increase surface area available to air flow, and arranged for efficient passage of air around the extruded heat sink, thus effecting efficient convection of heat into the air ambient. Cross cuts and fin are specifically arranged to enhance the “stack effect,” or “chimney effect,” associated with air flow. An objective is to maximize air flow across available surface area, and thus to enhance removal of heat into the air ambient.