DDR Memory is Everywhere

DDR memory is everywhere — not just in servers, workstations, and desktops, but also embedded in consumer electronics, automobiles, and other system designs. The DDR standard provides fast access to data stored in memory in a multitude of consumer devices, as well as in the data center. DDR5, the latest development of the standard, will provide double the bandwidth and memory capacity of DDR4 to support 400GE speeds in the data center.

The benefits of DDR5 in the data center

With 5G and IoT enabling billions of internet-connected devices, data center operators must find ways to meet ever-increasing data and storage demands, while preserving the quality of service and minimizing costs. Power is a premium resource for data center operators and minimizing power consumption is one of their top priorities to reduce operating expenses. Each new generation of DDR synchronous dynamic random-access memory (SDRAM) provides increased data transfer speeds, with more memory in a smaller package size that uses less power. Since power reduction is a critical requirement in mobile devices as well — due to the size and weight constraints of batteries — the JEDEC also introduced a low-power DDR (LPDDR) standard. As the name implies, the LPDDR standard uses lower signal amplitude, reducing power consumption.

DDR5 will provide double the bandwidth and memory capacity of DDR4, 6 gigatransfers per second (GT/s) and one terabit (Tb) of memory respectively, as well as improved power efficiency. DDR5 will provide the performance enhancements and power management needed in the data center to support 400GE networking speeds and enable the latency requirements of 5G.

DDR timeline

DDR5 introduces new design and test challenges

Compared to DDR4, DDR5 will provide faster speed, reduced footprint, and improved power efficiency. However, these improvements introduce new design and test challenges for chip designers and device manufacturers. Design error margins decrease, and signal integrity becomes more challenging to maintain. Test and measurement solutions enable DDR5 designers to optimize their transmitter, receiver, and channel designs for best performance and reliability at the increased data transfer rate of 6 GT/s. Selecting test tools that thoroughly test to DDR5 specifications for design and simulation, characterization, and validation will ensure the performance and interoperability of next-generation DDR5 devices.

Faster serial bus communications

In addition to faster memory, server speeds increased from 16 gigabits per second (Gbps) to over 30 Gbps in about a year, and future technologies may use PAM4 to push data rates above 50 Gbps to support 400GE in the data center.

PCI Express (PCIe) will evolve to PCIe 5.0 since PCIe 4.0, with a data rate of 16 GT/s, is no longer sufficient to support 400GE data center speeds. As a result, the PCI Special Interest Group (PCISIG), the standard body that defines the PCIe specifications, has fast-tracked the development of the PCIe 5.0 standard which is due for completion in 2019. With a data rate of 32 GT/s, PCIe 5.0 provides twice the throughput of PCIe 4.0.

In addition, new interconnect standards, such as Open Coherent Accelerator Processor Interface (OpenCAPI), Gen-Z, and Cache Coherent Interconnect for Accelerators (CCIX), offer alternatives to the PCIe standard. These bus standards specialize in areas where PCIe is not customized.

We live in a world that demands faster response times and increased bandwidth, to live stream our favorite movies or FaceTime with our friends and family. As my colleague Jessy wrote about in her blog, 5G Access in the Making - Are You Ready to Party?, 5G’s reach will go far beyond faster speeds and generate new experiences through augmented reality (AR) and virtual reality (VR) while enabling connected cars and giving rise to smarter homes. 5G will transform numerous industries including the automotive, industrial, and healthcare sectors. But none of the advantages of 5G can be realized if the data center and high-speed computing interfaces don’t continue to evolve as well. 2019 will be a year of data center revolution. Since standards evolve quickly from one generation to the next, test engineers can save significant time and get their designs to market faster using test solutions that ensure full compliance with industry standards.

For information on how Keysight’s solutions can help you address your high-speed computing interface design and test challenges, visit the following web pages: