Rambus, Microsoft Heat Up With Cold DRAM

　　A community of computer scientists striving to respond to soaring system demand for real-time data processing has just received some good news.

　　Rambus revealed Monday (April 17) that the company, in collaboration with Microsoft researchers, will have an early prototype of cryogenic memory in a month, and a more complete one by the end of the year. The new technologies will be essential to data centers, “currently the fastest growing consumer of memory” in the industry, Craig Hampel, chief scientist at Rambus, told EE Times.

　　The new memory subsystems will be able to operate below minus?180 °C or minus?292.00 °F or 93.15 kelvin. This will substantially reduce energy consumption and improve the overall performance of a bank of computers deployed in the cloud for massive data processing, he explained.

　　Rambus and Microsoft struck a deal in late December, 2015 to pool resources and develop memory systems for next-generation quantum computing.

　　Rambus’ announcement on Monday is the first tangible result of the joint efforts. Such cryogenic techniques mark a significant change in DRAM operating temperatures.

　　However, during the initial partnership announcement, the two companies did not mention the development of cryogenic DRAM. Instead, they appeared more interested in developing memory systems for next-generation quantum computing. So, how does their latest announcement relate to that?

　　Hampel explained that this all fits into a greater strategy to advance systems to superconducting computing and ultimately to quantum computing. Rambus explained that by breaking down the cryogenic systems’ long-term goal for quantum computing in bite size, they have applied the new technologies to prototyping DRAM that can operate below 90 kelvin.

　　The U.S. National Institute of Standards and Technology has chosen to consider the field of cryogenics as that involving temperatures below minus?180 °C or minus?292.00 °F or 93.15 kelvin (K).

　　Conventional DRAM operates at room temperature – roughly at 350 and 350 K. By cooling down to 90 K, “you bring down the leakage to zero, while achieving higher performance at a much lower temperature,” explained Hampel.

　　Once you bring the temperature down to 7 K, that’s when you get into the superconducting domain, he added. “It allows all of the interconnect power to become zero.”

　　To get to quantum computing, however, cryogenic memory must “operate at 20 to 40 millikelvin, which is essentially colder than deep space,” said Hampel.

　　Thus far, by succeeding in a DRAM prototype that works at colder than 90 K, Rambus is “hopeful,” said Hampel, that this leads to “better DRAM scaling, lowering cost and increasing reliability” in subsystems currently under tremendous thermal stress.

　　The goal is a cryogenic memory subsystem in the next two to three years, according to Hampel.

　　To get there, the Rambus-Microsoft partnership is still missing a third leg: DRAM and foundry suppliers. Rambus isn’t announcing that today but will soon need to address it.

　　In search of new memory architecture

　　Looking back on Rambus’ history, Hampel said, “We have always pushed the new memory architecture” in new markets. In the late ’80s to early ’90s, Rambus went after the PC market with its proprietary memory technologies, and ended up entangled in a standards war. Then, by mid-1990s, Rambus shifted focus to the video game console market, getting its RDRAM adopted by Nitendo 64 and Sony’s PlayStation.

　　As the growth of PCs and game consoles have slowed and smartphones are getting fragmented, Hampel said, “We approached Microsoft for partnership,” as both companies identified data centers as “the best home for new memory innovation.”