http://www.engadget.com/2010/11/19/pci-express-makes-the-3-0-leap-doubles-bandwidth-over-pcie-2-0/
the PCI-SIG has announced the availability of the PCIe Base 3.0 specification to its members today, and the highlights are certainly notable. There's a new 128b/130b encoding scheme and a data rate of 8 gigatransfers per second (GT/s), doubling the interconnect bandwidth over the PCIe 2.0 specification. And since we're sure you're fretting it, we'll go ahead and affirm that it maintains backward compatibility with previous PCIe architectures. We're also told that based on this data rate expansion, "it is possible for products designed to the PCIe 3.0 architecture to achieve bandwidth near 1 gigabyte per second (GB/s) in one direction on a single-lane (x1) configuration and scale to an aggregate approaching 32 GB/s on a sixteen-lane (x16) configuration