TECH TALK
PCIe Gen5 Is Coming
LAST ISSUE I talked about the upcoming switch to DDR5 memory for the next generation Intel and AMD platforms. Now, I want to talk about something we won’t see with AMD’s socket AM5, and most likely not on Intel’s LGA1700 Alder Lake CPUs either—at least, not on consumer parts. The specifications and requirements for PCI Express 5.0 are complete, and AMD and Intel will be supporting the tech soon enough, but initially only on data center hardware.
Jarred Walton
© INTEL
Intel’s Alder Lake may support PCIe Gen5, but most consumer motherboards will stick with Gen4.
Before anyone gets too upset, let’s talk about the reason behind the decision. PCIe signaling keeps getting faster, which requires tighter tolerances. Gen3 ran at a paltry 8 GT/s per lane (985MB/s to be precise), yielding a maximum throughput of about 16GB/s for an x16 slot. That’s fast enough for a lot of use cases, including gigabit Ethernet and even 10Gbps USB 3.2. The ubiquitous PCIe Gen3 now handles audio, USB ports, networking, and all the x1 to x16 expansion slots. The requirements are low enough that it’s possible to route all the motherboard traces to the further slots, and the power requirements are relatively tame.