Motherboard assembly

1. A motherboard assembly comprising:

a board body;

an expansion unit provided on said board body and defining a hybrid expansion slot that complies with the Peripheral Component Interconnect (PCI) specification and the Peripheral Component Interconnect Express (PCIE) specification; and

a riser card connected removably to said hybrid expansion slot and formed with at least a first expansion slot that complies with the PCI specification and a second expansion slot that complies with the PCIE specification;

wherein said hybrid expansion slot has two opposite sides, said expansion unit having 100 first conductive pins that are marked from A 1 to A 100 and that are formed on one of said sides of said hybrid expansion slot, and 100 second conductive pins that are marked from B 1 to B 100 and that are formed on the other of said sides of said hybrid expansion slot, said first conductive pins that are marked from A 1 to A 63 and said second conductive pins that are marked from B 1 to B 63 correspond to pins of the PCIE×16 specification, said first conductive pins that are marked from A 64 to A 100 and said second conductive pins that are marked from B 64 to B 100 correspond to pins of the PCI specification; and

wherein said riser card has conductive pins corresponding to said first conductive pins and said second conductive pins.

2. The motherboard assembly of claim 1 , wherein said first conductive pins that arc marked from A 1 to A 18 and said second conductive pins that are marked from B 1 to B 18 comply with the PCIE×1 specification.

3. The motherboard assembly of claim 1 , wherein said second expansion slot of said riser card supports at least one of the PICE×1 specification, the PCIE×4 specification, the PCIE×8 specification, and the PICE×16 specification.

4. The motherboard assembly of claim 3 , wherein said second expansion slot of said riser card supports the PCIE×1 specification and the PCIE×16 specification.