A cooling system for a computer system, said computer system comprising at least one unit such as a central processing unit generating thermal energy and said cooling system intended for cooling the at least one processing unit and said cooling system comprising, - an integrated element, said integrated element comprising a reservoir, a heat exchanging interface and a pump, ∘ said reservoir having an amount of cooling liquid, said cooling liquid intended for accumulating and transferring of thermal energy dissipated from the processing unit to the cooling liquid, said reservoir comprising a tube inlet connection, a tube outlet connection, a pump chamber and a thermal exchange chamber, ∘ said heat exchanging interface being in thermal communication with the processing unit and with the thermal exchange chamber, which thermal exchange chamber is adapted to have the cooling liquid flow along its surface resulting in direct heat exchange between the processing unit and the cooling liquid, ∘ said pump comprising an impeller, which is provided in direct communication with said pump chamber, said pump intended for pumping the cooling liquid into the reservoir, through the reservoir and from the reservoir to the heat radiator, - a heat radiator, which is arranged distant from the integrated element and its reservoir, where the tube inlet connection and the tube outlet connection of the reservoir are connected to the radiator via connecting tubes (24,25) through which the cooling liquid flows into and out of the heat radiator and into and out of the reservoir for radiating thermal energy from the cooling liquid to the surrounding of the heat radiator, wherein the inner surface of the heat exchanging interface facing the thermal exchange chamber is provided with a network of channels across the inner surface of the heat exchanging interface along which network of channels the cooling liquid is intended to flow, characterised in that, - said pump is a centrifugal pump and the pump chamber configures a cavity adapted to contain said impeller and a rotor of said pump and said cavity comprises a pump inlet and a pump outlet, the pump outlet provided tangentially to the circumference of the impeller, and - wherein said integrated element further comprises an intermediate member separating said thermal exchange chamber and said pump chamber wherein said exchange chamber comprises a first and a second passage for leading cooling liquid to and from said exchange chamber and wherein at least said first passage is provided in said intermediate member. - an integrated element, said integrated element comprising a reservoir, a heat exchanging interface and a pump, ∘ said reservoir having an amount of cooling liquid, said cooling liquid intended for accumulating and transferring of thermal energy dissipated from the processing unit to the cooling liquid, said reservoir comprising a tube inlet connection, a tube outlet connection, a pump chamber and a thermal exchange chamber, ∘ said heat exchanging interface being in thermal communication with the processing unit and with the thermal exchange chamber, which thermal exchange chamber is adapted to have the cooling liquid flow along its surface resulting in direct heat exchange between the processing unit and the cooling liquid, ∘ said pump comprising an impeller, which is provided in direct communication with said pump chamber, said pump intended for pumping the cooling liquid into the reservoir, through the reservoir and from the reservoir to the heat radiator, ∘ said reservoir having an amount of cooling liquid, said cooling liquid intended for accumulating and transferring of thermal energy dissipated from the processing unit to the cooling liquid, said reservoir comprising a tube inlet connection, a tube outlet connection, a pump chamber and a thermal exchange chamber, ∘ said heat exchanging interface being in thermal communication with the processing unit and with the thermal exchange chamber, which thermal exchange chamber is adapted to have the cooling liquid flow along its surface resulting in direct heat exchange between the processing unit and the cooling liquid, ∘ said pump comprising an impeller, which is provided in direct communication with said pump chamber, said pump intended for pumping the cooling liquid into the reservoir, through the reservoir and from the reservoir to the heat radiator, - a heat radiator, which is arranged distant from the integrated element and its reservoir, where the tube inlet connection and the tube outlet connection of the reservoir are connected to the radiator via connecting tubes (24,25) through which the cooling liquid flows into and out of the heat radiator and into and out of the reservoir for radiating thermal energy from the cooling liquid to the surrounding of the heat radiator, - said pump is a centrifugal pump and the pump chamber configures a cavity adapted to contain said impeller and a rotor of said pump and said cavity comprises a pump inlet and a pump outlet, the pump outlet provided tangentially to the circumference of the impeller, and - wherein said integrated element further comprises an intermediate member separating said thermal exchange chamber and said pump chamber wherein said exchange chamber comprises a first and a second passage for leading cooling liquid to and from said exchange chamber and wherein at least said first passage is provided in said intermediate member.