People often mistake the GPU for the Power Supply Unit. On an ATX motherboard, the GPU is on the video card or underneath it with a few leads plugged into pins on one edge of your motherboard.
gpu=graphics processing unit.
a GPU is connected to your motherboard via one or more DVI, HDMI, or display ports (depending on the model). The power supply sends current through that cord and then out to either the CPU cooler fan (to cool off something that’s running hot) -or- back down to power your PCI expansion cards like USB controllers & sound cards; what you see at both ends of this type of wire are called plugs (acceptable spelling.).