Intel to Integrate PCI Express 3.0 Support into Thunderbolt

Intel Outlines Thunderbolt Target: PCI Express 3.0

by Anton Shilov
03/09/2012 | 02:40 PM

Intel Corp. said earlier this week that it had begun works on improving speed and features of Thunderbolt interconnection to PCI Express 3.0 levels. Intel does not disclose any actual details of implementations or set dates at this point.


"We are working on integrating PCI Express 3.0 support into a future version of Thunderbolt, but are not prepared to get into more detail at this time," said Dave Salvator, a spokesman for Intel.

Thunderbolt technology supports two low-latency communications protocols - PCI Express for data transfer and DisplayPort for displays. Thunderbolt technology works on data streams in both directions, at the same time, so users get the benefit of full bandwidth in both directions, over a single cable. With the two independent channels, a full 10Gb/s of bandwidth can be provided for the first device in the chain of the devices. Intel's Thunderbolt controllers interconnect a PC and other devices, transmitting and receiving packetized traffic for both PCIe and DisplayPort protocols and thus makers need to develop or use additional controllers to make their products compatible with the TB I/O interface.

Essentially, Thunderbolt today is PCIe 2.0 x4 via cable, which provides 10Gb/s (2.5Gb/s*4). With PCI Express 3.0 in similar configuration, it would provide up to 20Gb/s speed with some PCIe 3.0 specific capabilities.

What is unknown is whether Thunderbolt featuring PCIe 3.0 will continue to use copper wires, like the existing Thunderbolt technology, or will use more expensive optical cables. Last April Intel said that its next-generation external interconnection technology (PTB, or post-Thunderbolt) will be based on silicon photonics components with optical cables and will be able to transfer data with up to 50Gb/s speed over distances up to 100 meters.

Since PTB is supposed to emerge sometimes in 2015, it is likely to expect Thunderbolt/PCIe 3.0 to emerge sometimes in 2013 or 2014.