The present invention discloses improved heatsink designs and methods for cooling a heat source. One embodiment is a heatsink assembly for removing heat from an electronic component, the heatsink assembly comprising a copper-based core section having a first surface generally adapted to conform to an exposed mating surface of an electronic device and a second surface having a generally convex curvature having a greater surface area than the first surface. An aluminum-based outer section has a first surface comprising a concave curvature that is generally adapted to conform to the convex curvature of the core and a second surface. A plurality of fin elements protrude outwardly from the second surface of the outer section. At least one cooling fan can be positioned to direct airflow onto the fin elements. The core section can comprise a semi-spherical shape and can be joined by a finger-joint type connection to the outer section. A key design element of the present invention is the speed in which the heat is transferred away from the heat source. Due to a concentration of material having greater thermal conductivity located near the heat source, heat is allowed to transmit further and faster away from the source than with previous heatsink designs and is distributed more evenly throughout the main heatsink structure.