A heat sink arrangement is provided for cooling first and second sets of electronic components positioned below the heat sink arrangement. This comprises: a first cooling element for cooling the first set of electronic components, wherein the first cooling element is a first heat sink comprising a base and a retaining wall that together define a volume for holding liquid coolant; and a second cooling element for cooling the second set of electronic components, configured to distribute liquid coolant over the second set of electronic components. The first and second cooling elements are arranged such that liquid coolant overflows from the volume of the first cooling element to the second cooling element for distribution over the second set of electronic components.