A cable electrical connector assembly includes an electrical connector, a cable soldered with the electrical connector, and an insulative body. The electrical connector includes a printed circuit board having a number of conductive pads, two of the conductive pads forming a differential signal pair for differential signal transmission. The cable has a number of core wires soldered with the conductive pads. The insulative body encloses a soldering area of the conductive pads and the cable core wires. The insulative body has a slot between the two conductive pads of the differential signal pair, the slot running through the insulative body along an up-to-down direction. The slot improves impedance in the soldering area of the core wires and the conductive pads.