A heat sink includes a base plate which is fitted against a component to be cooled, and a heat pipe formed as a loop having a condenser portion upstanding from the base plate and a pair of ends which form a pair of evaporator portions received in parallel channels in the base plate. A wall upstanding from the base plate between the channels is formed with an upright channel which receives the condenser portion substantially within the profile of the wall, so that a plurality of horizontal cooling fins can be fixed to the wall in thermal contact with the condenser portion.