The evolution of the PCI Express standard continues apace, with the finalization of 6.0 and the first steps towards 7.0.
Last year, the PCI Special Interest Group (PCI-SIG) - the body responsible for defining and finalizing the specifications for each generation of the PCI Express standard - laid down the technical specifications for PCI Express 6.0, which could see the light of day in our PCs as early as next year or, more likely, during 2025-26. In particular, PCI Express 6.0 promises to further boost the data rates offered by PC expansion connectors, with the x16 port reaching a whopping 128 GB/s. Even more impressive, the modest x1 port is expected to reach 8 GB/s, the same speed as the x16 of 2007's PCI Express 2.0!
PCI-SIG is not stopping there, and all the companies involved in the project have agreed on what are known as draft specs. In this case, we're talking about draft specs v0. 3, which aren't really new at all, since they date back to last year: they haven't yet been published, however, since they're not yet fully official. Unsurprisingly, such specifications are subject to change, even if the trend is towards a further doubling of data rates compared with the PCIe 6.0 standard.
This doubling will allow throughputs of 256 GB/s on the x16 and even 512 GB/s thanks to the use of bi-directional transfer. To achieve such a result, PCIe 7.0 doesn't seem to need any change in signal technology, as the PAM4 already used on PCIe 6.0 is still on the program. On the other hand, PCI-SIG insists on the need to work on two other objectives: improving energy efficiency on the one hand, and maintaining hardware compatibility with previous generations of the PCI Express standard on the other. It's true that the opposite would make a mess.
At present, therefore, we're only talking about draft specifications, but the PCI-SIG is confident of being able to publish the final characteristics of the standard before the end of 2025. Remember that the PCIe 5.0 standard had been finalized in 2019, but that its deployment is just beginning within our "mainstream" PCs. It therefore seems rather optimistic to see PCIe 7.0 for 2027, even if the technology has every chance of being ready.
