64-bit computing Intel and AMD's 64-bit architectures can offer users a more efficient and lower cost alternative to running 32-bit applications on dedicated 64-bit servers
The 64-bit system architecture has been used in Unix/Risc servers for more than a decade, and Intel introduced the first generation of its 64-bit Itanium platform, "Merced", in 2001.
Although users can run existing 32-bit x86 applications on 64-bit systems such as IBM Power and Sun Sparc, the price/performance ratio is often unattractive. As a result, users have confined their 64-bit application workloads to 64-bit servers optimised to meet their performance requirements. Now, AMD and Intel's x86 64-bit derivatives make it possible for suppliers to build higher-volume, lower-cost 64-bit servers.
Forrester's research has shown that, at the end of 2003, more than 24% of firms were using AMD Opteron. A sizable portion of users coupled Linux and open source applications on Opteron-based x86 servers. In addition, Sun has launched a full AMD Opteron-based portfolio (targeting up through eight-way servers in 2005), and Hewlett-Packard has entry and mid-range Opteron-based Proliants (currently up through four-way servers).
Microsoft also opened the door for AMD in 2003 with its plan to produce 64-bit native versions of Windows for AMD Opteron and Athlon 64. This forced Intel to accelerate its plans to extend its 32-bit x86 Xeon and Pentium processors to support 64-bit application workloads. Users should expect the two premier x86 chipmakers to target an ever-increasing base of performance-hungry applications at the same aggressive price/point as the 32-bit computing segment.
Benefits of 64-bits
The 64-bit architecture offers up to 1Tbyte of physical addressable memory - an enormous improvement on the 4Gbytes memory in today's 32-bit processor client-side and server-side designs.
This additional capacity allows compute- and data-intensive applications to store vast amounts of data in the main memory and avoid the performance penalty of swapping data back and forth between the main memory and the hard disk.
Not every application needs the memory boost of 64-bit, but the value of this new architectural enhancement is that it offers an easy upgrade path.
Because Intel's EM64T Xeon/Pentium and AMD's Opteron/Athlon chips extend the 32-bit x86 architecture, firms can either continue using 32-bit apps or adopt a full 64-bit ecosystem including applications, device drivers, tools and compilers. Furthermore, 32-bit apps running on an x86-based Opteron or EM64T client or server system with a 32-bit OS will get a performance boost over running the same applications on previous-generation 32-bit x86 systems.
Windows on x64
Microsoft also plans to release 64-bit native versions of Windows. Evaluation versions of 64-bit versions of Windows XP (known as Windows XP Professional x64 Edition) and Windows Server 2003 (known as Windows 2003 Enterprise x64 Edition) have been available since January 2004.
Both are pre-release products, meaning they are at the final prerelease testing and qualification stage, and Microsoft expects them to ship soon. The firm also announced the Technology Exchange Program for PC and server users, which will allow buyers of existing 64-bit machines to exchange their 32-bit Windows OS licenses for the equivalent x64 versions after Microsoft releases them. However, upgrading the OS will require a clean install.
When Microsoft releases Windows XP Professional x64 Edition, Intel plans to launch desktop Pentium 4 processors with 64-bit support. Intel will also introduce 64-bit Pentium M and Celeron processors throughout 2005.
On the server side, Intel launched "Nocona" - the 64-bit version of Xeon - in August 2004, ahead of the final release of Windows Server 2003 Enterprise x64 Edition. The release of Extended Memory 64-bit Technology (EM64T) - Intel's 64-bit extension to the x86 32-bit architecture - is a tacit acknowledgement that extending the x86 architecture is an approach customers will more readily accept.
The launch of x86 64-bit technology will bring volume and economies of scale to the server market where customers need to bring additional application workload performance to existing 32-bit environments.
Over time, this trend will nullify the higher cost of running 64-bit applications on Intel's two- to four-processor Itanium architecture and will protect customers' investments in existing 32-bit applications by allowing them to run them on new 64-bit machines.
AMD has aggressively courted HP, the only supplier with a full range of two 64-processor Itanium-based servers, and HP already ships Proliant-branded AMD Opteron-based servers up to four ways.
Dell and IBM have made only limited commitments to Itanium in their entry level. They will only produce one- to four-processor servers in 2005 and Forrester expects they will also release Opteron and Intel Xeon with EM64T-based multicore servers in both four-way and eight-way processor configurations in 2005.
Strategy for 64-bit adoption
Data-intensive application workloads, such as computer-aided engineering, business analytics and databases will drive 64-bit adoption. Applications will generally fall into one of four application workload scenarios.
Intel Xeon-based 32-bit x86 servers remain the most cost effective technology for running lower-priced 32-bit infrastructure software such as web servers and file and print servers.
The vast majority of client-side applications, such as office productivity suites, do not need the performance boost offered through extended memory. Therefore, most general business PC users will stick with 32-bit applications without worrying about the architecture of the processor.
However, with both Intel and AMD focusing all their PC processor research and development efforts on 64-bit, it is reasonable to assume that most PC buyers in 2006 will be buying 64-bit machines, regardless of whether or not their OS and apps are 64-bit.
Today, infrastructure applications such as Dynamic Host Configuration Protocol servers and domain controllers largely operate satisfactorily as 32-bit. However, the applications will scale and perform better with a 64-bit OS and processor combinations under the hood.
Unix users will continue to run high-performance technical computing applications on 64-bit Unix/Risc systems, such as Sun Microsystems' Sparc and IBM's Power5-based systems, as well as on Intel Itanium 2.
These applications have complex transactional and data analytics, large data sets and heavy processing loads and require a full complement of many 64-bit optimised feature sets (eg 64-bit hardware, OS, drivers, compilers and software development tools).
Although the introduction of the Linux 2.6 kernel closes the gap between feature and functionality between Unix and Linux, customers will still lean toward Unix on Risc alternatives, most notably on Power5 and Itanium 2, for high-end, heavy-lifting applications that require maximum symmetric multi-processing-based performance scalability thresholds.
Simon Yates is an analyst at Forrester Research
This was first published in February 2005