A new generation of Peripheral Component Interconnect, PCI Express is an I/O interconnect bus standard that expands on and doubles the data transfer rates of original PCI.
PCI Express is a two-way, serial connection that carries data in packets along two pairs of point-to-point data lanes, compared to the single parallel data bus of traditional PCI that routes data at a set rate.
Initial bit rates for PCI Express reach 2.5 Gbit/s per lane direction, which equates to data transfer rates of approximately 200 MB/s.