This 8-pin power extension cable is needed on modern EPS, ATX and BTX mainboards for supplying power to the processor. In contrast to the older, 4-pin ATX12V Mainboard- and power supply connections, this connection has double the width, 2x 4-pin. The connector can be split into two 4-pin connectors on the mainboard side, from which one of them also fits the older mainboards. Even only a 4-pin connector can be inserted onto the other 8-pin side individually, the other 4 pins then do not receive any current. Please read the instructions provided by the mainboard manufacturer.