Intermediate heat sink (20-I) for a liquid cooling system for an electronic board, said electronic board including at least one electronic component, said system comprising a cold plate for receiving said heat sink (20-I), said cold plate being sized to at least partially cover the electronic board and comprising a cooling circuit including channels inside which circulates a so-called "cold" heat transfer fluid for supplying at least said heat sink (20-I), and a discharge circuit including channels inside which circulates a so-called "hot" heat-transfer fluid having been heated through the heat sink (20-I), the heat sink (20-I) comprising a cooling block comprising a lower portion constituting the main heat exchange zone and an upper portion which is intended to be connected to the cold plate, the intermediate heat sink (20-I) being characterised in that it comprises: - a so-called "cold" inlet connector intended to be fluidically connected to a cold outlet connector of an upstream heat sink (20-E) and fluidically connected to the upper portion of said cooling block so that said cooling block is supplied with cold heat transfer fluid, - a so-called "hot" inlet connector intended to be fluidically connected to a hot outlet connector of an upstream heat sink (20-E) and fluidically connected to the upper portion of said cooling block, - a so-called "hot" outlet connector intended to be fluidically connected to a hot inlet connector of a downstream heat sink (20-S), - a so-called "cold" outlet connector intended to be fluidically connected to a cold inlet connector of a downstream heat sink (20-S), the upper portion of the cooling block being configured to: - divide the flow of heat transfer fluid entering through the cold inlet connector into a first flow, which is directed towards the lower portion of the cooling block so as to collect the heat generated by the electronic board by being routed to the hot outlet connector, and a second flow which is directed directly towards the cold outlet connector, - route the flow of heated heat transfer fluid received at the hot inlet connector directly towards the hot outlet connector. - a so-called "cold" inlet connector intended to be fluidically connected to a cold outlet connector of an upstream heat sink (20-E) and fluidically connected to the upper portion of said cooling block so that said cooling block is supplied with cold heat transfer fluid, - a so-called "hot" inlet connector intended to be fluidically connected to a hot outlet connector of an upstream heat sink (20-E) and fluidically connected to the upper portion of said cooling block, - a so-called "hot" outlet connector intended to be fluidically connected to a hot inlet connector of a downstream heat sink (20-S), - a so-called "cold" outlet connector intended to be fluidically connected to a cold inlet connector of a downstream heat sink (20-S), - divide the flow of heat transfer fluid entering through the cold inlet connector into a first flow, which is directed towards the lower portion of the cooling block so as to collect the heat generated by the electronic board by being routed to the hot outlet connector, and a second flow which is directed directly towards the cold outlet connector, - route the flow of heated heat transfer fluid received at the hot inlet connector directly towards the hot outlet connector.