PCI sig at IDF
September 13, 2010, Intel developer forum, San Francisco—The PCI-SIG, the controlling organization for the PCI interface specifications, announced the upcoming release of PCIe (PCI express) version 3.0. This latest revision is scheduled for final publication and distribution in November of this year. It’s currently in the membership final review phase at member companies.
The PCI bus is an open standard for all areas of I/O and the new version doubles bandwidth and optimizes power compared to PCIe 2.0. The table below lists comparisons between the various standard implementations.
In addition to overall increases in speed, the encoding is changed from 8b/10b to 128b/130b. This encoding scheme is more efficient and reduces the performance overhead of the earlier encoding scheme. As a result, the bandwidth is doubled without requiring extensive redesign of the hardware interfaces. As has been the practice in previous generations, this latest specification is backward compatible to all previous specifications.
Protocol extensions are intended to improve interconnect latency power and platform efficiency. Some of these extensions include data reuse hints, atomic operations, dynamic power adjustment mechanisms, bio page faults, bar resizing, and loose transaction ordering.
Electrical and mechanical specifications are also being enhanced. The latest specification includes dynamic feedback equalization to optimize signal-to-noise ratio at the simple point of the receiver. This equalization will improve signal integrity while providing maximum flexibility under different channel conditions. Card electromechanical characteristics will consolidate previous form factor power delivery specifications and also previous topologies for clients and servers. Some other form factors are being introduced as well as standard cables and connectors for various width links.
The organization expects to have complete test specifications including electrical, protocol, and configuration requirements available by the end of year. Hardware and software tools will include fixtures, electrical, bios, and configuration confirmation and inspection tools. The organization is planning a compliance workshop for later this year. The PCI-SIG estimates that 3.0 products starting to appear in the second half of next year.
