PCI EXPRESS 6.0

The PCI Express 6.0 standard has now been released. It is expected to be available in servers by 2021. Consumer products will be likely in 2022. The biggest need for more bandwidth is with the M.2 slot for SSD products.

PCIe 6.0 Specification Features

  • Delivers 64 GT/s raw bit rate and up to 256 GB/s via x16 configuration
  • Utilizes PAM-4 (Pulse Amplitude Modulation with 4 levels) encoding and leverages existing 56G PAM-4 in the industry
  • Includes low-latency Forward Error Correction (FEC) with additional mechanisms to improve bandwidth efficiency
  • Maintains backwards compatibility with all previous generations of PCIe technology

The massive buildup in bandwidth is needed for some servers who suffer from bottlenecking. This much bandwidth will also blur the line between RAM and SSD products leading to a new possibility for machine designs.

DDR3 is about 40 GB/s and DDR4 can manage about 80 GB/s which will pressure designs to some extent. Static RAM is faster which may be needed to handle bottlenecks.

“Continuing the trend we set with the PCIe 5.0 specification, the PCIe 6.0 specification is on a fast timeline,” Al Yanes, PCI-SIG Chairman and President, said. “Due to the continued commitment of our member companies, we are on pace to double the bandwidth yet again in a time frame that will meet industry demand for throughput.”

Eventually PCIe 6.0 will surface with gaming machines. The main hardware that can take advantage is the SSD which seems to be poised to ramp up in speeds. Graphics cards have no need for even PCIe 2.0 bandwidth. The M.2 SSD slot is close to the CPU so it can be ramped up for faster speed assuming that SSD vendors can continue to developer faster controllers.

The CPU to southbridge link is usually the most demanding on a motherboard. The southbridge is usually tasked with SATA, USB and secondary slots along with other devices. Integrated WiFi usually uses an M.2 key B slot. USB 4.0 is likely to be more demanding with various merged protocols and this will influence designs. It remains to be seen if USB speeds will ramp up above 80 gigabit speeds.