(pē-sē-ī ik-spres´)
(n.) An
I/O interconnect
bus standard (which includes a
protocol and a layered
architecture) 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
Gb/s per lane direction, which equate to data transfer rates of approximately 200
MB/s. PCI Express was developed so that high-speed interconnects such as
1394b,
USB 2.0,
InfiniBand and
Gigabit Ethernet would have an I/O architecture suitable for their transfer high speeds.
PCI Express, also known as 3GIO (for third-generation Input/Output) is compatible with existing PCI systems.