PCIe 6.0 standard now official

PCIe speeds compared. © PCI Special Interest Group.

While PCIe 5.0 standard products are just beginning to show up on the market, version 6.0 is getting the finishing touches. Version 6.0 doubles the bandwidth (64 GT/s instead of 32) and energy efficiency compared to the PCIe 5.0 specification. To boost its speeds, PCIe 6.0 uses a new kind of signaling called Pulse Amplitude Modulation 4 (PAM4), which allows for faster data transfers than the previous Non-Return-To-Zero (NRZ) signaling at the expense of a higher error rate. To compensate, PCIe 6.0 includes technologies like Forward Error Correction (FEC) to correct errors and Cyclic Redundancy Checking (CRC) to ask for packets to be retransmitted when errors can’t be corrected.

The PCIe 6.0 architecture maintains compatibility with all previous generations of PCIe. This allows any existing hardware that uses earlier specs to work in PCIe 6.0 hosts, which will certainly make it easier to adopt and transition to this new spec. While PCIe 5.0 is still in its infancy, we shouldn’t expect to see PCIe 6.0 hardware for another 12 to 18 months, and then likely in the business server realm to begin with. At present, version 4.0 remains the most common standard for high-end products, while 3.0 released in late 2010 is still used in many budget SSDs.

⇨ Ars Technica, Andrew Cunningham, “PCIe 5.0 is just beginning to come to new PCs, but version 6.0 is already here.”

⇨ AnandTech, Ryan Smith, “PCI Express 6.0 Specification Finalized: x16 Slots to Reach 128GBps.”

2022-01-12