The adoption of the latest DRAM is always dependent on whether the supporting ecosystem makes it easier to design products and meet system requirements. For DDR5, it now includes Rambus’ Serial Presence Detect (SPD) Hub and Temperature Sensor.

The latest entry to the company’s portfolio of DDR5 memory interface chips for data centers and PCs complements its Registering Clock Driver (RCD) announced in late 2021. “Rambus has been mostly focused on line speed signal, integrity–type chips, like the RCD,” said John Eble, VP of product marketing for memory interface chips at Rambus. The company is looking to expand its portfolio by taking advantage of technology changes to enable DDR5 and provide more intelligence and control, he said.

A key characteristic of DDR5 is it achieves increased memory bandwidth and capacity by employing a new module architecture with an expanded chipset — thereby placing increased premium on signal integrity and thermal management for server and client Dual Inline Memory Modules (DIMMs). Rambus’ SPD Hub and Temperature Sensors improve DDR5 DIMM system management and thermal control to support higher performance within the desired power envelope for servers, desktops, and laptops.

As components on a memory module, the SPD Hub and temperature sensor gather important data for system configuration and thermal management. The SPD Hub is used in both server and client modules, including RDIMMs, UDIMMS, and SODIMMS, while the temperature sensor is designed for server RDIMMs, Eble said.

In concert with the array of fans and a management controller orchestrating the system, the new Rambus offerings help to manage thermals and optimize the performance of the DDR5 DIMM by providing a more granular understanding of temperature in the system, he added.

The information gathered allows the system to make more intelligent decisions about fan speed, the refresh rate of the DRAM on the DIMM, and throttle the CPU bandwidth to let the temperature settle down in extreme scenarios, Eble said. The temperature sensor has alarms that can be set and the I3C serial interface support allows for the system to be monitored for flagged behaviors.

He said these kinds of memory interface chips enable the DDR5 ecosystem to reflect the increased number of modules in a server and the resulting channels per socket. “As bandwidth goes up, things get more complex. It becomes more difficult to control the temperature and the thermals.”

Beyond having these ecosystem pieces in place, Eble said DDR5 adoption will be heavily influenced by CPU advancements, particularly that of Intel. Alder Lake supports DDR5 and is already shipping, and Rambus is seeing many customers that are carrying out DDR5 qualifications. “The next big event which is going really drive the DDR5 adoption is the Sapphire Rapids launch.”

CPUs are getting hotter, he added, and the addition of more PCIe slots and SSDs in a server are also contributing to the increased heat. “Air cooling is still the king in the data center.”

— Gary Hilson is a general contributing editor with a focus on memory and flash technologies for EE Times.

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Gary Hilson is a freelance writer and editor who has written thousands of words for print and pixel publications across North America. His areas of interest include software, enterprise and networking technology, research and education, sustainable transportation, and community news. His articles have been published by Network Computing, InformationWeek, Computing Canada, Computer Dealer News, Toronto Business Times, Strategy Magazine, and the Ottawa Citizen.

Gary Hilson is a freelance writer and editor who has written thousands of words for print and pixel publications across North America. His areas of interest include software, enterprise and networking technology, research and education, sustainable transportation, and community news. His articles have been published by Network Computing, InformationWeek, Computing Canada, Computer Dealer News, Toronto Business Times, Strategy Magazine, and the Ottawa Citizen.

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