A computing unit configured to be mounted in a High-Performance Computing cabinet, thereafter HPC cabinet, defining a plurality of vertically stacked sockets, the computing unit comprising: • an external body configured to engage with at least one of the sockets, the external body comprising at least a bottom wall and two lateral walls defining a housing comprising a front housing opened from the front and a back housing where primary electronic components are located, each lateral side comprising an abutment wall configured to be secured directly to the HPC cabinet, the external body comprising at least a first connector connected to the primary electronic components, • an internal body, comprising secondary electronic components (A0-A3, 6, 52, 53), the internal body being releasably coupled with the external body when mounted on the front housing in order to allow extraction of the internal body when the external body is secured fixedly to the HPC cabinet, the internal body comprising at least a second connector connected to the secondary electronic components (A0-A3, 6, 52, 53), the second connector being configured to cooperate with the first connector when the internal body is coupled with the external body, • the internal body comprising: i. a bottom tray, comprising bottom secondary electronic components (A0-A3) and at least a bottom connector connected to the bottom secondary electronic components (A0-A3), the bottom tray comprising front fans, ii. a top tray being releasably coupled with the bottom tray, the top tray comprising top secondary electronic components (6, 52, 53) and at least a top connector connected to the top secondary electronic components (6, 52, 53), the top connector being configured to cooperate with the bottom connector when the top tray is coupled with the bottom tray, the top tray comprising two ventilation ducts configured to guide the air flow from the front fans to the back housing of the computing unit. • an external body configured to engage with at least one of the sockets, the external body comprising at least a bottom wall and two lateral walls defining a housing comprising a front housing opened from the front and a back housing where primary electronic components are located, each lateral side comprising an abutment wall configured to be secured directly to the HPC cabinet, the external body comprising at least a first connector connected to the primary electronic components, • an internal body, comprising secondary electronic components (A0-A3, 6, 52, 53), the internal body being releasably coupled with the external body when mounted on the front housing in order to allow extraction of the internal body when the external body is secured fixedly to the HPC cabinet, the internal body comprising at least a second connector connected to the secondary electronic components (A0-A3, 6, 52, 53), the second connector being configured to cooperate with the first connector when the internal body is coupled with the external body, • the internal body comprising: i. a bottom tray, comprising bottom secondary electronic components (A0-A3) and at least a bottom connector connected to the bottom secondary electronic components (A0-A3), the bottom tray comprising front fans, ii. a top tray being releasably coupled with the bottom tray, the top tray comprising top secondary electronic components (6, 52, 53) and at least a top connector connected to the top secondary electronic components (6, 52, 53), the top connector being configured to cooperate with the bottom connector when the top tray is coupled with the bottom tray, the top tray comprising two ventilation ducts configured to guide the air flow from the front fans to the back housing of the computing unit. i. a bottom tray, comprising bottom secondary electronic components (A0-A3) and at least a bottom connector connected to the bottom secondary electronic components (A0-A3), the bottom tray comprising front fans, ii. a top tray being releasably coupled with the bottom tray, the top tray comprising top secondary electronic components (6, 52, 53) and at least a top connector connected to the top secondary electronic components (6, 52, 53), the top connector being configured to cooperate with the bottom connector when the top tray is coupled with the bottom tray, the top tray comprising two ventilation ducts configured to guide the air flow from the front fans to the back housing of the computing unit.