A heat sink is provided. The heat sink comprises a hollow chassis having a contact face at a bottom portion thereof for attaching to an electronic component and a heat dissipating face at a top portion thereof. A plurality of circularly arranged fins extend from an inner sidewall of the hollow chassis towards a center of the hollow chassis so that gaps between the fins gradually decrease from the inner sidewall of said hollow chassis towards the center of said hollow chassis. At least a heat pipe is positioned between the contact face and the heat dissipating face. At least a fan is positioned at a side of the hollow chassis for generating air to increase an amount of air blowing through wider gaps between said fins to increase the speed of heat dissipation.