High-speed memory race gets new entrant

Electronic News, Nov 3, 1997 by Will Wade

Mountain View, Calif.--Hyundai Electronics Industries and Mitsubishi Electric have delivered the first test high-speed SLDRAM chips to the SLDRAM Consortium. The group hopes to sample a 64 megabit chip by next spring, and plans to publicly demonstrate systems using the technology at the Comdex '98 trade show.

With microprocessor speeds outstripping memory chip performance by a significant factor, main memory is becoming a bottleneck and SLDRAM is one of several next-generation technologies promising high-speed performance to solve this growing problem. SLDRAM will join double data rate DRAM (DDR DRAM) in the upcoming battle to dominate the main memory market, but both face an uphill struggle against high bandwidth titan Rambus.

And, perhaps to make the climb easier, both SLDRAM and DDR DRAM manufacturers are aiming their chips at high-end servers and workstations. SLDRAM is also being positioned for the notebook and inexpensive desktop market, but these marketing strategies demonstrate that both camps have abandoned to Rambus the high ground of desktop PC main memory.

"We want to position SLDRAM at both the low-end and the high-end," said Farhad Tabrizi, chairman of the SLDRAM Consortium. That means expensive workstations, and low-cost PCs, areas where he does not expect Rambus to be a strong force. "Rambus DRAM (RDRAM) will not be appropriate for servers and workstations. We believe Intel will want to use Rambus in their high-end desktop systems, but we don't believe Rambus will fit in their sub-$1,500 PCs."

Playing Catch-up

While there are currently no systems running with any of these technologies, both SLDRAM and DDR DRAM have a lot of ground to make up against Rambus. Initial DDR DRAM chips may appear next year, while RDRAM samples are already available.

Rambus technology is expected to run at speeds approaching 800MHz, while DDR DRAM's data transfer frequency is a lower 200MHz. SLDRAM has promised to reach 400MHz. Depending on how the devices are measured, with various calculations involving the pincount and frequencies, each claims to reach a total bandwidth of 1.6G. Nonetheless, most observers see Rambus as the fastest technology, moving more data per pin than the others.

Rambus' strength is in its future commitments and licensing agreements, notably Intel which has committed to design systems using RDRAM starting in 1999. Almost every major DRAM manufacturer, along with many MPU and memory component company, has signed agreements to manufacture or utilize Rambus technology in some manner. This has left competing technologies to pick around the edges of the memory market.

DDR DRAM manufacturer Hitachi is developing a 256M chip which it hopes to sample next year. Brett Etter, DRAM product marketing manager at the company, said such high-density DDR DRAM chips will be best suited for servers and workstations with heavy memory demands. He also conceded that Rambus will likely dominate the desktop PC segment, which represents some two-thirds of the memory chip market.

Mr. Etter stressed that DDR DRAM and Rambus, which both deliver high bandwidth, are similar but equal. "We can both do 1.6 gigabits-per-second, but do it in different manners," he said. "So each one is better for different applications. They have different capabilities."

Delivery May Be The Differentiator

It is unclear whether these marketing strategies are based upon actual differences between the technologies, or a pessimistic evaluation of the future memory market. Jim Handy, memory analyst at market research firm Dataquest, downplayed the idea that one chip is more appropriate for different segments of the market than another. "I would not say there are significant differences," he said.

According to Mr. Handy, neither SLDRAM nor DDR DRAM has much chance to displace Rambus in the desktop PC main memory market. "I wouldn't be surprised if they were abandoning the PC space. They have to prove they will be available in volume by the time Intel is ready to use them," he said. While DDR DRAM is a bit more tangible than SLDRAM, he said neither is close to Rambus' schedule for delivering actual silicon.

While personal computers are a huge chunk of the memory market, Rambus executives insist their chips will dominate other segments as well. Subodh Toprani, VP and general manager of Rambus' logic products division, said RDRAM was specifically designed to satisfy the needs of the entire memory spectrum. "We do believe the device is the best solution for a multitude of applications," he said. "There will be exceptions of course, but for the bulk of mainstream desktops, notebooks and workstations I think we will dominate. We don't want to hang our hat on just one segment; in general we want to be the technology that's broad-based."

Most memory manufacturers have their feet planted in several camps. Almost every member of the SLDRAM Consortium has also licensed Rambus, and many of them are also working on DDR DRAM. There is very strong demand to develop an open protocol for high-speed memory in order to get around paying licensing fees to Rambus.