Server vendors focus on memory in Nehalem-EX servers

Orthodox server designs are receiving a face-lift with Intel's Nehalem-EX processor, with vendors implementing new memory features to boost application performance.

Intel on Tuesday 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 Center Group, during a Nehalem-EX launch event in San Francisco. 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 virtualization, 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.

With the new server architecture, users can buy only the memory they need instead of buying servers, Bradicich said. "Incrementally adding only the needed resources is much more efficient and economical and reduces the server sprawl plaguing data centers today," he said.

Dell has introduced patent-pending FlexMemory technology specifically for the Nehalem-EX servers, which can scale the memory capacity without adding new hardware. The new technology is silicon that manages and manipulates the memory in order to double capacity, overcoming limitations that typically throttle the amount of memory that can fit in servers.

The new technology could help double the number of virtual machines in virtualized environments without increasing software licensing costs, said Brian Payne, senior planning manager for the Dell PowerEdge server line. Software licensing costs could be tied to the number of cores on a chip, but adding memory capacity on the fly will make workloads easier to move without adding cores or memory modules, Payne said.

Dell on Tuesday introduced two rackmount servers: the PowerEdge R810, which will run on Nehalem-EX chips, and the PowerEdge R815, which will run on Advanced Micro Devices' 12-core Opteron 6100 chips, released on Monday. A two-socket R810 server supports 512GB of memory, which is double that of the R815 server, Payne said.

NEC is also relying on larger memory capacity as one area to boost performance, said Mike Mitsch, general manager for the IT platform group at NEC Corporation of America. The company on Tuesday introduced NEC Express5800/A1080a server, which will run Nehalem-EX chips and include up to eight sockets and up to 2TB of memory capacity.

"Exploiting the four memory channels implemented into the Nehalem-EX was one of the key areas of the architecture," Mitsch said.

The company redesigned the server to take advantage of the buffering technology offered by Intel for Nehalem-EX servers. In traditional x86 systems -- like servers with Intel's recently released Xeon 5600 chips -- the clock speed of memory declines as more memory slots are loaded, but buffering technology isolates the loading factor to keep the memory operating at the highest frequency, Mitsch said.

"You can increase the amount of memory without sacrificing the speed," Mitsch said.

NEC is already taking orders for the server, which may start shipping in May, Mitsch said. The list price of the server starts at US$53,000 with 128GB of memory.