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It has been over 10 years now since PCI Express has been evolving to the stage where the data rate has tripled. Next in line for the PCI Express standard is version 4.0 which the PCI SIG [special interest group] has been developing PCI Express 4.0 since late 2011. PCI SIG also has claimed that the fourth generation PCI express standard will be finalized be the year 2017 with implementation sometime after then although we have not seen and more info on actual release.
PCI Express 4.0 will utilize a new connector, but the specification will be backward compatible mechanically and electrically with PCI Express 3.0, which means that it will be possible to use today’s add-in-cards in PCIe 4.0-based systems, but future add-in-cards will not work with PCIe 3.0.
According to engineers, 16GT/s base transfer rate will allow PCI Express 4.0 x1 interconnection to transfer up to 2GB of data per second, whereas the PCI Express 4.0 x16 slots used for graphics cards and ultra-high-end solid-state drives will provide up to 32GB/s of bandwidth. This outstanding bandwidth was not thought possible a few years back. Since there will be less time for data to transfer; this will have benefits for mobile users such as power saving. There will be more to come on PCI Express 4.0 as more information is released.