PCI-SIG, the group that handles the PCI spec, has finalized the upcoming PCI-Express 3.0 spec. The new PCI spec set to debut in 2009 or 2010 will boast a transfer rate of 8GT/s or 8 GigaTransfers/second.

PCIe 1.1 and 2.0 use 10 bits of encoding to send 8 bits of data. This, in turn, results in theoretical peak transfer rates that are only 80 percent as fast as the number typically expressed by the group when using the nomenclature GigaTransfers per Second. A PCIe 1.1-compliant system has a peak transfer rate of 2.5GT/s or 2Gbps/s. PCIe 2.0 doubles this to 5GT/s or 4Gb/s. As a result, PCIe 3.0 actually doubles the theoretical peak transfer rate of PCIe 2.0 in terms of Gb/s.

PCI-SIG