Intel Nehalem-EX widens server memory bandwidth

Intel this week announced new Nehalem-EX processors, which will include up to eight cores and are targeted at high end applications like databases and real-time business intelligence, said Kirk Skaugen, vice president and general manager of Intel's Data Centre Group. The new chips include changes that provide faster access to memory, and IBM, NEC and Dell have changed designs to take advantage of those features.

Intel has put four memory channels in Nehalem-EX processors to increase memory bandwidth. Servers with Nehalem-EX could also include separate buffered memory chips to temporarily store data alongside the main memory for faster execution. Beyond the number of cores, system performance depends on a number of factors like on-chip cache and memory, said Jim McGregor, chief technology strategist at In-Stat.

Intel's memory enhancements are an important step forward as the company tries to push the x86 architecture into the high end server market, which is dominated by IBM's Power, Oracle/Sun's Sparc and Intel's Itanium processors, McGregor said. System vendors have typically tried to distinguish x86 server offerings based on the number of cores and virtualisation, but memory could become a major distinguishing factor for server vendors trying to enter the high-end server market.

"The increased memory capability is huge. It really does open up more applications," McGregor said. Large chunks of information can be moved to the memory quicker for faster processing, he said. Lack of memory is a major performance inhibitor for many applications in servers, said IBM Fellow Tom Bradicich. If database applications are to be robust and high-speed, large amounts of data need to access the memory very quickly, he said.

"This can result in a large number of disk accesses, and spinning disks are among the slowest components in the server. Memory is among the fastest components in the server, and with extra memory, we can speed up the access," Bradicich said.

Bradicich is one of the architects of IBM's new eX5 server architecture, which decouples memory and processors into separate units. The memory is stored in a 1U drawer that IBM says packs 600 percent more memory. Internal server RAM may not be enough for some applications, and with eX5, IBM is extending the memory capacity of servers, Bradicich said.

The memory drawer is connected to a server by a specially designed chip to reduce latency. IBM has said that the new eX5 servers will run on Nehalem-EX chips, though the company didn't comment on release dates.