The group responsible for developing and updating the PCI Express standard, the PCI-SIG, aims to update this standard approximately every three years. Version 6.0 was released earlier this yearand the group has announced that PCIe version 7.0 is currently on track to be finalized sometime in 2025. Like all new PCI Express versions, the goal is to double the available bandwidth of its predecessor, which in the case of PCIe 7.0 means a single PCIe 7.0 lane will be transmitting at speeds of up to 32 GB per second.
That’s double the 16GB per second promised by PCIe 6.0, but it’s even more striking when compared to PCIe 4.0, the version of the standard used in high-end GPUs and SSDs today. A single PCIe 4.0 lane provides a bandwidth of approximately 4 GB per second, and you have eight of those lanes to provide the same speeds as a single PCIe 7.0 lane.
Increasing speeds open the door to ever-faster GPUs and storage devices, but such large bandwidth gains would also allow the same amount of work to be done with fewer PCIe lanes. Today’s SSDs normally use four lanes of PCIe bandwidth and GPUs normally use 16 lanes. You could use the same number of lanes to support more SSDs and GPUs, while still offering a big increase in bandwidth compared to today’s accessories, something that can be especially useful in servers.
As with all previous versions of the PCIe standard, the PCI-SIG says that PCIe 7.0 devices remain fully backward compatible with older PCIe versions. There’s some coding overhead that makes real-world accessories reach the full 32GB per second speeds promised by PCIe 7.0, but that’s true of all PCIe versions.
It will be a year or two before we start seeing PCI Express 6.0 in consumer PCs, not to mention version 7.0. Intel’s latest 12th-generation Alder Lake processors include a limited number of PCIe 5.0 lanes, and PCIe 5.0 will also be part of AMD’s Ryzen 7000 series later this year. But consumer GPUs and SSDs using PCIe 5.0 still don’t really exist. Most new standards take years to go from “draft” to “finished” to “available in shipping products” to “ubiquitous”, and new PCI Express versions are no exception.