The PCI-SIG consortium announced PCIe 7.0 nearly four years ago and no products supporting it have come to market yet, but the standards body is going forward with the first draft of the PCIe 8.0 standard. If all goes according to plan, the final PCIe 8.0 specification will be released in 2028.

Each new revision of the PCIe spec features a doubling of performance over the prior generation, and 8.0 is no different, with 256 GT/s data rate and 1 TB/s of raw bi-directional bandwidth via a 16-lane configuration, double that of PCIe 7.0.

PCIe is the standard interface for hard drives, networking cards, and graphics cards. That includes GPU based accelerators. PCI-SIG,  the standards body leading the development of the PCIe spec, says it is being designed for workloads like AI/ML, high-speed networking, and edge computing running in hyperscale data centers.

“With the increasing data throughput required in AI and other applications, there remains a strong demand for high performance. PCIe technology will continue to deliver a cost-effective, high-bandwidth, and low-latency I/O interconnect to meet industry needs,” said Al Yanes, PCI-SIG president and chairperson in a statement.

In theory, PCIe Gen8 NVMe SSDs will be rated for sequential speeds of up to 120,000 MB/s. By contrast, a PCIe 6.0 SSD can reach about 28,000 MB/s sequential read in.

Pulse Amplitude Modulation with 4 levels (PAM4) signaling, first added to the PCIe spec in 6.0 as a replacement for non-return-to-zero (NRZ) amplitude, we’ll see further refinement to helpPCIe 8.0 achieve its high transfer rates.

PCI-SIG also says development has focused on connector technology, latency, forward error correction (FEC), reliability, protocol-level bandwidth optimizations, and lower power consumption. Backward compatibility with older PCIe generations is also being given high priority.

There is a significant difference between how PCIe is used on desktops versus servers. On the client side, things have settled on PCIe 5 and there has been no rush to 6. That’s because the benefits of PCIe 6 are oriented towards servers and desktops and notebooks get no real benefit from adopting PCIe 6.

The situation is completely different on servers, where maximum throughput is needed and the benefits of new technologies like PAM4 are evident. Upcoming server CPUs, such as AMD’s Zen 6-based Epyc processors and Intel’s Diamond Rapids Xeon processors, both due this year, are expected to support PCIe 6.0. Meanwhile, PCIe 7.0 is finished and waiting at in the wings for OEMs when they are ready.