A server cabinet includes a rack and a server unit installed in the rack. The server unit includes a receiving portion extending rearward from a rear wall of the server unit adjacent to a sidewall of the server unit, a motherboard with a first connector, and a cable with a second connector. The motherboard is received in the server unit. The first connector is received in the receiving portion. The receiving portion defines a through hole adjacent to the sidewall. The second connector of the cable extends through the through hole, to be connected to the first connector of the motherboard.