A heat sink (100) includes a cooling block (105) having a plurality of
fins (110) extending through the block to provide a series of coolant
channels (112) extending between the fins, the channels having in the
interior of the block a venturi narrowing. Beneficially, the channels
have coolant entry regions in at least two different regions (115, 120)
of the block to direct a plurality of coolant flows into the interior of
the block from different directions.Also described is a method of cooling
a device such as a processor of a mobile computer used in a vehicle by
placing the heat sink or more than one of the heat sinks adjacent to the
device to be cooled, preferably with a region in which the venturi
narrowing of the coolant channels is provided close to the hottest part
of the device to be cooled.