A cooling assembly having a base plate and a condenser plate. An outer wall interconnects the base plate to the condenser plate to define a sealed chamber with a working fluid being disposed within the sealed chamber. Intersecting partition walls are mounted to the condenser plate and are angled downwardly toward the base plate for directing working fluid on the condenser plate down a corner of the walls toward a portion of the base plate. Preferably, the base plate defines a first circumference and the condenser plate defines a second circumference larger than the first circumference such that the outer wall has an angled configuration extending between the base plate and the condenser plate to provide a larger area within the sealed chamber for a vapor phase of the working fluid than a liquid phase of the working fluid.