October 27, 2017 // 10:52 a.m.
The Peripheral Component Interconnect Special Interest Group (PCI-SIG) has officially announced the final revision of the PCI Express 4.0 (PCIe 4.0) specification, promising data rates of up to 16 gigatransfers per second (16GT/s) and reduced system latency over the PCI Express 3.0 specification.
Announced back in June this year, PCI Express 4.0 brings a doubling of bandwidth over PCI Express 3.0: 8 gigatransfers per second (8GT/s) and 8Gb/s of link bandwidth per lane for a total of 32GB/s per 16-lane slot in PCIe 3.0 has become 16GT/s and 16Gb/s for a total peak throughput of 64GB/s per 16-lane slot. The new specification also includes changes for additional lane-width configurations, designed to give card and motherboard designers more flexibility alongside the current 1x/4x/8x/16x layouts, lower minimum speeds when power draw is a concern, reductions to system latency, and improved scalability.
'The delivery of the PCIe 4.0 specification to the industry is an important addition to our spec. library as it delivers high performance 16GT/s data rates with flexible lane width configurations while continuing to meet the industry’s requirements for low power,' claims the PCI-SIG's Al Yanes. 'And we've seen unprecedented early adoption! Prior to publication, we've had numerous vendors confirmed with 16GT/s PHYs [Physical Layers] in silicon and IP vendors already offering 16GT/s controller. Given the interest, we held a pre-publication Compliance Workshop with preliminary FYI [For Your Information] Testing Only for PCIe 4.0 architecture that attracted dozens of solutions. We’re continuing to conduct FYI testing in our workshops throughout the remainder of the year.'
The launch of the finalised PCIe 4.0 specification comes ahead of schedule, but PCI-SIG is already turning its eyes to its successor PCIe 5.0. Currently sat at version 0.3, Yanes says PCI-SIG is to target a second-quarter 2019 release of the specification which will bring a second doubling in performance to 32GT/s.
The PCIe 4.0 specification is available free of charge to PCI-SIG member companies via the official website, though non-members wishing to dive down into the nitty-gritty will be disappointed to hear copies cost a whopping $4,500 each.