Are ARM-based servers the next big trend?

Future ARM-based servers could reduce power costs in the data center, helping cloud service providers such as Microsoft.

Servers based on low-power system-on-chip (SoC) architectures from ARM Holdings currently exist in a nascent stage. However, speculation about such servers running Windows was increased after Microsoft announced in early January that its next-generation Windows operating system (possibly called "Windows 8") will be designed to run on ARM chips.

Microsoft's announcement at the Computer Electronics Show (CES) in Las Vegas was about ARM-based PCs -- and not about servers. However, that announcement still marked a noteworthy change. Microsoft has worked for years with Intel and AMD on making Windows and Windows Server work with x86 chips for PCs and servers. ARM traditionally hasn't played a role in that landscape.

Still, ARM Holdings is no stranger to a Windows collaboration. The Cambridge, UK-based licensor of SoC architectures has had a 13-year partnership with Microsoft on the Windows Compact Embedded OS used for mobile devices. The new partnership deal on ARM-based processors running "Windows Next" likely will take some time to bear fruit. Products might not be seen until late 2012, given Microsoft's past OS development cycles.

ARM-based processors are mostly seen today in mobile devices, particularly Linux-based consumer devices, but the chips are notable for their low-power consumption. ARM's architectural designs are for 32-bit chips, but that seems likely to change given the trend toward new 64-bit PCs. The company was supposed to have announced plans for 64-bit designs late last year, according a Computerworld article.

If ARM eventually will be good to go with the next Windows desktop OS, why wouldn't it work with the next Windows Server? It seems possible, since Microsoft's desktop and server OSes now share the same code base.

Data center Power Reduction

Reducing power consumption in the data center would help make hosted applications more affordable on a mass scale. Such a prospect would be a powerful incentive for Microsoft to work with ARM on server technology. It could help prove Microsoft's business case and cut costs for other organizations running cloud services or datacenters.

A 2007 "Commodity Data Center Design" presentation (PowerPoint download) by James Hamilton, formerly an architect with the Microsoft Data Center Futures team, estimated that "power is 40 percent of DC [data center] costs." Hamilton jumped ship from Microsoft in January of 2008, joining the Amazon Web Services team as vice president and distinguished engineer.

Microsoft is also touting the overall environmental benefits associated with the use of its cloud computing platform. Organizations accessing Microsoft's online applications use less power than if they ran those same applications from local servers, Microsoft claims.

Chipmakers Working on ARM-Based Servers

A handful of the smaller chipmakers have already focused their operations on creating CPUs for servers based on the ARM architecture. For instance, ZT Systems announced in November that it has built an ARM-based server solution using up to 16 ARM Cortex A9 processor cores. The company's R1801e 1U Server product has a "system maximum power draw of less than 80 Watts," according to a Nov. 18 announcement issued by Secaucus, N.J.-based ZT Systems.

Marvell rolled out a server platform based on four ARM v7-based 1.6 GHz cores back in November. The Santa Clara, Calif.-based company claims that its Armada XP processor can power enterprise cloud computing applications at low power, which is defined as "16,600 DMIPS [Dhrystone million instructions per second] performance at less than 10 watts." Power consumption at 10 watts is roughly equivalent to that of a clock radio, according to a U.S. Department of Energy estimate.

Another builder of ARM-based chips for servers is Austin, Texas-based startup Calxeda. The company has secured $48 million in funding from partners and venture capital firms to build a server-on-chip product based on "a new generation ARM processor," according to the company's Web site.

Even big chipmaker Nvidia is getting into the act.

"NVIDIA is joining Marvell and Calxeda (previously Smooth-Stone) in taking the ARM architecture and targeting server-side computing," James Hamilton explained in a Jan. 16 blog post. Nvidia's collaborative efforts are associated with its "Project Denver" effort to build ARM-based CPUs, according to Hamilton.

If that weren't enough, IBM has teamed up with ARM, although on a consumer mobile electronics deal associated with ARM's Cortex processors, according to a Jan. 17 announcement by ARM. However, Richard Fichera, vice president and principal analyst at Forrester Research, speculated in a blog post that this partnership deal might bode well toward some future IBM collaboration on ARM-based servers.

In an earlier blog post, Fichera affirmed that servers built on ARM-based processors was a viable idea, adding that they might save power compared with x86 offerings, and might incorporate graphics processing units (GPUs) for added processing power.

"The latest ARM offering is the Cortex A9, with vendors offering dual core products at up to 1.2 GHz currently (the architecture claims scalability to four cores and 2 GHz)," Fichera wrote. "It draws approximately 2W, much less than any single core x86 CPU, and a multi-core version should be able to execute any reasonable web workload. Coupled with the promise of embedded GPUs, the notion of a server that consumes much less power than even the lowest power x86 begins to look attractive."

Directions on Microsoft analysts also recently commented on Microsoft's ARM partnership announcement. They too affirmed the prospects for ARM-based servers.

Possible Clash With Intel and AMD

ARM-based servers may lead to an industry shakeup of sorts. A November white paper (PDF download) from Clabby Analytics, "Will ARM Servers Usurp Intel Xeon?," suggested that the new ARM-based processors for servers might use 20 percent of the power consumed by Intel Xeon chips while costing half the price.

The authors of the white paper also confirmed IBM's interest in "the concept of ARM servers," although they stressed that IBM hasn't make any commitments. ARM-based servers would support the bottom line in datacenters.

"The growth of ARM combined with an intensifying need to get power consumption in the data center under control, is leading us to believe that ARM could be 'the next big thing' in computer architecture," the Clabby Analytics white paper concludes.

It's likely that Intel and AMD won't stand still to see their dominant x86-based server market chipped away by upcoming ARM-based server offerings, should that come to pass. At the CES event, Microsoft CEO Steve Ballmer announced that Intel and AMD also were developing SoCs for next-generation Windows PCs.

Servers already exist that use Intel's currently available low-power Atom chips, which are widely deployed in netbooks. Santa Clara, Calif.-based SeaMicro claims that its SM10000 server uses "less than 2 KW of power," according to the company's Web site. The SM10000 server has 512 processors based on 1.6 GHz Intel Atom chips.

However, Fichera questioned whether Intel Atom chips could compete.

"It looks like a dual-core ARM CPU at 1.2 GHz should outperform a single-core atom (the few benchmarks that exist comparing low-end x86 CPUs with ARM CPUs seem to indicate a higher performance per clock cycle for the ARM processor)," he wrote in his blog post.