One year after the 0.7 revision of the PCI Express 4.0 specification, version 0.9 is in turn being finalized. The members of the PCI-SIG organization are thus called to carry out the review of the specifications before August 7, with a final version before the end of the year, either two years late.
The PCI Express 4.0 doubles the bit rate of 3.0 to reach 16 GT / s, always with 128b / 130b encoding or almost 2 GB / s for each line in each direction. This gain will be via the frequency, in return the usable connections without chips to resynchronize the signal will be shorter.
As a reminder, while PCI-SIG originally thought that this version 4.0 would be the last one using copper tracks, a version 5.0 was announced a year ago. Its specifications 0.3 are currently being reviewed by members. If the rhythm is the same as for version 4.0 we can expect a final version by 2020/2021, since the target rate is not yet public.
