We frequently see DDR SDRAMs as a key specification of computers and digital devices. In this two-part guest commentary, Ben Miller from Keysight Technologies shares his insights into the design of DDR SDRAMs (Part 1) and how faster memory speeds shape the future (Part 2).
DDR5 is still in the early phases of adoption. JEDEC released the standard in July 2020. The first CPU platform to support DDR5 was released in early 2022.
However, this platform still includes DDR4 support, so it could be some time before the industry accepts DDR5 as the de-facto memory standard and fully transitions memory systems to the new standard.
Faster memory enables the future
Over the next couple of years, more personal computers, servers, and embedded systems will take advantage of the higher speed, lower power, and greater memory capacity available with DDR5.
Doing so will open many new possibilities for high-speed networking and data processing.
Internet-of-Things (IoT) and Vehicle-to-Everything (V2X) autonomous vehicles are just two of the many technologies being enabled by 5G and 400 gigabit Ethernet which will connect billions of new devices to cloud services.
The data storage infrastructure required to process all that data will need quicker and more efficient memory than anything we’ve seen yet, especially in time- and safety-critical applications like V2X.
Outfitting servers with DDR5 will be a huge step, alongside adopting faster wireless communication, to enabling these new technologies.
But as these applications become reality, will DDR5 be fast enough?
DDR6: Doubling the data rate of DDR5
DDR5 is just starting to be adopted into the market, but JEDEC and early-adopters are already looking forward to the next generation.
DDR6 is likely to double the maximum bit rate of its predecessor, as all previous DDR generations have done.
One memory manufacturer announced in late 2021 that they have begun development of DDR6 with JEDEC, and that the standard could hit speeds of greater than 12,000 MT/s while quadrupling the memory capacity.
The New Reality
Until DDR6 becomes a reality, developers will continue to make the move from DDR4 to the new DDR5 standard.
Adapting products to updated standards takes time.
The slightly more complicated nature of the DDR5 standard, including adding equalization to the specification, means that simulation, design, validation, and compliance tests all become trickier and margins for error are even smaller.
But for many engineers, the faster bit rate speeds are worth the changes.
Their customers will likely agree, from competitive gamers and data center technicians to developers of AI and autonomous vehicles.
Faster memory is key to faster data processing for many essential applications.
But considering the speed challenges discussed previously, reaching this incredible bit rate goal will require even more innovation to successfully transmit the signal faster without causing significant, data-altering distortion.
One possibility is for DDR6 to take after other standards like Wi-Fi and Ethernet by using pulse amplitude modulation (PAM) or even quadrature amplitude modulation (QAM) signaling.
DDR5 already set the precedent for adding more data processing to the standard, so it makes sense that more complex signaling methods may be used in the next generation to increase the bit rate further.
By the Shannon-Hartley Theorem, which quantifies the maximum bit rate possible through a given channel, DDR4 currently takes up only about 10% of the capacity of a DIMM’s interconnects.
Unlocking the other 90% between now and the arrival of DDR6, without losing data bits to distortion, is the primary challenge for JEDEC’s engineers.
If they can solve the puzzle, they could lay the foundation for more data-driven technologies in the future.
Tags: byline, commentary, DDR, interviews, Keysight, memory, opinion, RAM, SDRAM, Tech Focus, technology
Wow they’re talking about DDR6 already?!
Yes. That’s the look ahead. We’re still in the midst of transiting from DDR4 to DDR5.