PCI Express Gen 3 Simplified

The PCI-SIG, an industry organization dedicated to developing and enhancing PCI/PCI Express (PCIe) technology, has successfully developed the PCI, PCI-X and PCIe Gen 1 and Gen 2 interconnect protocols and promoted the deployment of these technologies since PCI's inception in 1992.

In early 2008, the PCI-SIG announced the establishment of a workgroup chartered with the development of the next generation of PCIe " the PCI Express Base Specification 3.0, or PCIe Gen 3.

The Gen 3 specification is yet another step forward in enhancing the usefulness of the PCIe protocol by doubling the effective bandwidth and adding protocol enhancements to increase end-system performance.

Leading up to this development, IBM and Intel in 2006 launched an initiative called Geneseo, proposing extensions to the PCIe protocol for high-performance computing and visual processing.

Recommendations from this initiative were provided to the PCI-SIG as potential PCIe protocol enhancements. In addition to the adoption of Geneseo, several other engineering change notices (ECNs) were released by the PCI-SIG, providing enhancements for the efficiency and usefulness of the PCIe protocol.

This article will shed light on the PCIe Gen 3 standard, as well as some of the key enhancements that will be implemented in PCIe Gen 3 components.

Ten key enhancements have been completed and will be implemented in next-generation PCIe devices and systems. Some of these enhancements may get implemented into PCIe Gen 2 devices, while others will only be supported in Gen 3 products. Let's take a closer look at some of these enhancements (Table 1) approved as ECNs to the PCIe specification.

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