NEC to unveil memory technology at Comdex

Electronic News, Nov 17, 1997 by Will Wade

Las Vegas, Nev.--NEC Electronics will introduce this week at Comdex '97 a new DRAM core design which it says improves memory performance without increasing cost or die size. The company is offering Virtual Channel Memory (VCM) as an open architecture, and hopes to see additional firms begin producing the devices. However, initial industry response has been skeptical and so far there are no firm second-source agreements in place.

"Memory is becoming the main bottleneck in today's systems," said Will Mulhern, product marketing manager for advanced DRAMs at NEC. "VCM offers immediate performance improvements without changing board layouts. Our objective is to establish this as the industry standard core technology."

A Core Enhancement

VCM is a core enhancement which can work with all major types of main memory, including standard DRAM, EDO DRAM, synchronous DRAM, SRAM and VRAM, as well as upcoming technologies such as double data rate DRAM, direct Rambus DRAM and SLDRAM. While most of the next generation memory technologies have focused on increasing speed through improving the main interface, VCM speeds up the actual functioning of the memory cores.

The basic idea behind the design is to assign a specific space in the main memory array to every application with memory demands, which the company terms memory masters. This could include various software applications, peripheral devices, the operating system or network demands. The virtual channels function as a buffer which routes data to its predetermined location through a 1,024-bit bus. The design supports up to 16 individual channels.

Mr. Mulhern asserted that linking each memory master to a specific location in the main array allows the chips to perform more efficiently. Initial simulations comparing memory performance for a graphics application using Rambus DRAM and VCM-enhanced RDRAM are claimed by NEC to show large blocks of data moved through the pipe 22 percent faster with the VCM chip, and smaller blocks moved 40 percent faster.

Adding VCM capabilities to memory chips did not require significant increases to either size or cost, and he stressed that the products would use the same packaging as existing devices. "We can bring this out at comparable commodity memory prices."

Target: PC Main Memory

The new memory technology is aimed at PC main memory, workstations and servers, and graphics applications. "It is suitable for anywhere that memory is acting like a bottleneck," he said. NEC's initial VCM chip will be a 64-megabit SDRAM, which will sample next April. The company plans to add SGRAM and DDR DRAM units later next year. NEC is also talking to other memory manufacturers about adopting the architecture.

That's a good idea, according to Jim Handy, memory analyst at market research firm Dataquest. "History has shown that the devices which sell in high-volume are the ones which are widely sourced, and the things which have not sold in high-volume are the ones which are sole sourced," he said.

Mr. Handy also noted that the VCM idea is very similar to an earlier memory enhancement, Mitsubishi's cache DRAM (CDRAM), which is several years old and still selling at nearly 300,000 units per month, but has never taken off as a mainstream technology.

"The basic concept is the same," said Steve Forman, product manager for Mitsubishi Electronics America. "Cache DRAM and VCM are similar in that both have cache on the chip." CDRAM has found its niche in arcade games and high-end PCs used for graphics applications, and while the concept is open for anybody to use, no other memory company has demonstrated an interest in second-sourcing the product.

Other memory companies are taking a wait-and-see attitude. "We currently have no plans to implement this core into products but will continue to investigate it," said Bob Eminian, director of strategic marketing for memory leader Samsung Semiconductor's memory division. "It can take years to achieve stable, reliable, high-volume yields and minimum costs on a new core. Our immediate focus is on interface improvements such as DDR DRAM and direct RDRAM."

"Frankly, we need to do lot more study," said Mark Ellsberry, VP of marketing at Hyundai Electronics America. "The DRAM business is at a crossroads, and there are many, many new architectures being proposed. We are searching to find the one or two architectures that really add significant performance advantages."