MOTHER-BOARD

A mother-board includes a chipset, a switch, and first and second PCI Express X16 graphics interfaces. The switch has first and second switch circuits. The switch selectively turns on one of the first and second switch circuits according to a control signal. The first PCI Express X16 graphics interface has former eight lanes electrically connected to the chipset, and latter eight lanes selectively electrically connected to the chipset through the first switch circuit. The second PCI Express X16 graphics interface has former eight lanes selectively electrically connected to the chipset through the second switch circuit. When the first switch circuit is turned on, 16 lanes of the first PCI Express X16 graphics interface are electrically connected to the chipset. When the second switch circuit is turned on, the former eight lanes of the second PCI Express X16 graphics interface are electrically connected to the chipset.