PCI Express: Now with 8 gigatransfers per second; coming to a system near you in three years
The PCI Special Interest Group, or PCI-SIG, this week announced the speeds of the latest evolution to the PCI Express specification – PCI Express 3.0, also known as PCIe 3.0. PCIe 3.0 doubles the transfer rate of PCIe 2.0, bringing overall throughput to 8 gigatransfers per second, or GT/s.
PCI-SIG is designing the PCIe 3.0 standard for increased performance, but maintain backwards compatibility with PCIe and PCIe 2.0 devices. The group managed to double throughput of the existing PCIe 2.0 standard by removing the 8b/10b-encoding scheme used and additional optimizations. The 8b/10b-encoding scheme took 20 percent overhead on the overall raw bit rate, according to the group. The PCIe 3.0 standard also includes new signaling and data integrity enhancements.
"Backwards compatibility was a strong selling point for allowing our customers to migrate their technologies to the future technology, knowing that they had the connection point of being able to plug in older adapters and new adapters into existing whichever, whether it was an old or new platform,” Chairman and President of PCI-SIG Al Yanes said in an interview. “This backwards compatibility we're maintaining with the 8GT spec.”
PCIe 3.0 remains in development and isn’t slated for finalization until 2009. The group doesn’t expect industry adoption of the upcoming standard until 2H 2010-2011 timeframe, according to Yanes. The group is unsure which companies will support the upcoming PCIe 3.0 specification, but hints there are 900 companies that are part the PCI-SIG group that push the technology.
“Graphics has been a strong proponent of PCI Express, they've always lead the charge of adopting a new generation,” Yanes said. “There's no reason to think this is any different. We certainly think graphic vendors will be a strong supporter with PCIe 3.0,” he added.
In addition to doubling the transfer speeds of PCIe 2.0, the group is actively looking at new protocol extensions for PCIe 3.0, according to Yanes. The group wants to enhance the specification with better efficiency and power management techniques through protocol extensions.
“We're also actively pursuing protocol extensions to take PCI Express efficiency and latency improvement to the next level,” he added.
Expect PCI-SIG to release the official PCIe 3.0 specification in 2009.
|