A year ago, we wrote about AMD’s big Opteron processor launch, introducing the hardware by explaining its capabilities, outlining its requisite software components, and laying down sales strategies based on the platform’s strengths. As it turned out, AMD was taken seriously in the server and workstation markets for the first time. Six months later, the Athlon 64 emerged, bestowing the same valuable feature set on high-end and midrange desktop machines. Not surprisingly, it was also a smash hit and AMD reestablished the favor it once held with the fickle enthusiast community.

All the while, Intel persisted in its push for performance through megahertz, which is why the Pentium 4 is peaking at 3.6GHz today. It also pioneered a number of significant technologies along the way, a fact that reflects in Intel’s high-end desktop chipset, the 925X. Yet, through product introductions and smaller manufacturing processes, Intel resisted the adoption of 64-bit computing on the desktop, instead directing attention to its purebred enterprise platform, Itanium.
In somewhat of a forced hand, however, Intel swallowed its pride this past February during IDF (Intel Developer Forum) and announced a server processor that’d feature a number of improvements, including x86 64-bit extensions to compete with AMD’s Opteron. Why does Intel’s revelation matter to you? To begin, the same server and workstation customers to whom you cater with the benefits of AMD’s architecture will want to know about Intel’s alternative.But more important, Intel is committed to incorporating the 64-bit extensions into its 90nm Pentium 4 once Microsoft releases Windows XP in 64-bit trim. Acknowledging Intel’s move today will better prepare you for the proliferation of 64-bit technology in desktop machines tomorrow.

Laying the Hardware Infrastructure

Because the new Xeon processor, formerly referred to as Nocona, is architecturally different from its predecessor, Intel designed a new platform to complement it. The E7525 MCH (memory controller hub), intended specifically for workstations and mid-range servers, supports up to two Xeon processors on an accelerated 800MHz front side bus. It’s a shared bus, meaning that dual-CPU configurations must intelligently divvy front side bus bandwidth. In contrast, AMD’s Opteron resides on a point-to-point bus where each device has access to dedicated memory bandwidth, improving performance. Nevertheless, there’s much more bandwidth to share at 800MHz than the previous incarnation of Xeon, which was limited to 533MHz.
It also communicates with up to 16GB of DDR2 memory through a 128-bit memory bus, yielding up to 6.4GB per second of bandwidth with at least one pair of 64-bit modules installed. But whereas Intel’s high-end enthusiast chipset works with the fastest DDR2 memory at 533MHz, the E7525 zeroes in on stability and is limited to registered 400MHz modules. At the same time, Intel is quick to point out the power-saving characteristics of DDR2 memory (purportedly up to 40 percent), important, it says, in dense rack server configurations.
Perhaps the most notable change is an evolutionary shift away from the standard AGP and PCI buses, both of which will slowly give way to PCI Express. A x16 PCI Express graphics slot bodes well for demanding graphics workstation applications. In fact, ATI recently demonstrated one of its PCI Express graphics cards editing high-definition video in real time, an application enabled by the faster interconnect. Many server boards based on Intel’s E7525 are expected to include a PCI Express x8 slot as well, though some manufacturers might opt for dual x4 slots instead. According to Intel’s documentation, the wider x8 slot would be useful for adding high-speed networking devices, which could run at up to 16Gbps with significantly lower latencies than a 133MHz PCI-X interface.
The E7525 doesn’t include Intel’s fresh ICH6 south bridge. It instead features the more proven ICH5, which offers two Serial ATA ports with RAID 0/1 and eight Serial ATA ports. There will undoubtedly be motherboards that also come with Intel’s 6700PXH 64-bit PCI Hub, allowing for PCI Express, PCI-X (133MHz), and PCI connectivity all on the same platform.

Intel’s Xeon with EMT64

Of course, the center of Intel’s server and workstation world is the Xeon processor itself. There are actually several incarnations of Xeon in its modern form, beginning when Intel first unveiled its NetBurst micro-architecture at 1.5GHz and culminating with the current flagship clocked at 3.6GHz, featuring 1MB of on-die L2 cache. Each step of the way, Xeon has borne a resemblance to the Pentium 4, and the current flagship is no exception.

Manufactured on Intel’s maturing 90nm lithography process, Xeon incorporates a 1MB L2 cache, like the Pentium 4, runs on an 800MHz front side bus, like the Pentium 4, boasts Hyper-Threading support, like the Pentium 4, and the 13 new SSE3 instructions – you guessed it – like that Pentium 4. It differs in its support for dual-processing (that’s four logical CPUs, if you count the contributions of Hyper-Threading), DBS (demand-based switching), and EMT64 (Extended Memory 64 Technology). Demand-based switching is a renamed marketing term for SpeedStep, a mechanism capable of lowering an idle processor’s clock frequency and voltage. The result is less thermal output, lower power consumption, and slower fan speeds, yielding less noise. Incidentally, DBS is very similar to AMD’s Cool’n’Quiet technology, supported exclusively by the Athlon 64. Neither the Athlon 64 FX nor Opteron families wield the feature, giving Intel a leg-up, especially in constrained rack server applications.

EMT64 is arguably the most buzz-worthy piece in the Xeon puzzle. Intel describes it simply as a natural extension to its IA-32 architecture for greater memory access, and from a very simple point of view, that’s what it is. Like the AMD64 initiative, EMT64 infuses Xeon with the ability to run on any number of corresponding 64-bit operating systems, addressing in excess of 4GB of system memory. And because EMT64 includes provisions for a greater number of registers (temporary storage spaces on the processing core), it should handle 64-bit applications with a bit more alacrity.

Software, Strictly Speaking

In order for Intel’s Xeon to utilize its EMT64 capability, it must be used with a compatible platform featuring an enabled BIOS, 64-bit device drivers, and a 64-bit operating system. Applications re-compiled for 64-bit operation will exploit the technology, while older 32-bit programs will run in a compatibility mode.The resulting flexibility is one of the reasons we were so enthusiastic about AMD’s Opteron. Your customers have access to full-speed 32-bit performance today on their existing spread of software applications, and they are free to migrate to 64-bit as their own needs and abilities dictate.

Of course, the principle caveat to adopting 64-bit processing is an immediate shortage of software support. There are several properly enabled builds of Linux, but most small and medium businesses don’t need the massive database applications designed to work with SuSE 9.1 or Red Hat Enterprise Linux 3. Rather, Microsoft is the key partner, and it still hasn’t finished Windows XP 64-bit Edition. Fortunately for Intel, 64-bit device driver development is and has been an ongoing process beginning with AMD’s Opteron launch. The resulting infrastructure will serve to benefit anyone who buys a Xeon with EMT64 today.

What About Itanium?

processor in Intel’s armada. Its champion, Itanium 2, is still lurking about, intended for enterprise computing where 64-bit computing is a necessity and not a luxury. Itanium is still a relatively low-volume part compared to the latest desktop chips armed with 64-bit extensions, though, and it boasts diverging strengths.

A recent IDC whitepaper sponsored by Intel highlights three key differences between the two architectures. Perhaps the most obvious is Xeon’s native 32-bit performance. Itanium is backwards compatible with older 32-bit x86 applications, but it is optimized for memory addressability, parallel processing, and its EPIC architecture. Conversely, the Xeon handles common 32-bit apps with ease, demonstrating an additional benefit on 64-bit code by addressing to more than 4GB of system memory. Secondly, the IDC report claims that although the Xeon and Itanium boast similar integer performance, the latter is significantly faster in floating-point applications common to scientific and enterprise usage models. Finally, while Intel designed the Xeon and Itanium with provisions for reliability, Itanium is said to be the more stable platform. And because it features larger caches and a compiler-optimized architecture, Itanium is considered better for scaling, too.

Intel is considering ways to reduce the price of Itanium, even in light of its efforts to differentiate the capabilities of Itanium versus those of Xeon. It seems likely that the revamped Xeon will eat into Intel’s short-term goals for Itanium 2, but there are already plans to make the Itanium and Xeon fit into interchangeable socket interfaces by 2007, a move that should serve to reduce the cost of single and dual-processor Itanium machines. But even today, Intel believes the two architectures can coexist, so long as it draws a distinct line between the ideal usages of each. Industry analysts aren’t so sure, though. Unless Itanium comes down significantly in price, the allure of 64-bit computing on a multi-processor Xeon or Opteron server will increase as the chips gain support.

AMD’s Two Cents

Very rarely does Intel follow AMD’s lead in evangelizing technology. It happened before when AMD adopted DDR memory while Intel insisted on RDRAM. However, embracing 64-bit technology is a much more momentous leap for the firm that previously downplayed an immediate need for 64-bit processing, as it validates AMD’s mantra. And while it seems reasonable that Intel’s change of heart would threaten the potency of AMD’s Opteron and Athlon 64 families, AMD doesn’t think so. “Welcome to the 64-bit party,” says AMD’s Damon Muzny. “By incorporating support for our 64-bit extensions, Intel is doing something good for itself, something good for us in validating its relevance, and something good for the industry, which we hope will accelerate the software infrastructure for AMD64.”, and is better suited for servers and workstations.

Knowledge is Power

Even if your opportunities to sell server and workstation-class hardware are limited, Intel’s Xeon launch is still important. The representatives to whom we spoke made it clear that by the time Microsoft’s 64-bit version of Windows XP emerges, pulling the technology within reach of enthusiast and mainstream users alike, Intel will be offering a desktop implementation of EMT64 on its existing Pentium 4, which is architecturally very similar to the Xeon. When that happens, you can expect the Pentium 4 and Athlon 64 to offer similarly competitive feature sets and comparable performance, too.

We’ve already talked to game developers such as Valve Software and Epic Games, both of whom advocate pushing 64-bit computing. Moreover, German developer Crytek has already committed to patching its immensely popular Far Cry game for 64-bit functionality. Even if 64-bit computing doesn’t accelerate a majority of desktop applications, game developers maintain that there’s addition performance to be had in their lush virtual worlds thanks to the flexibility of 64-bit processing.
With a fundamental understanding of Intel’s latest technology and its inherent benefits, you’ll be able to pitch Xeon machines to SMBs and 64- bit equipped Pentium 4 systems to home users, when the time comes. And since the Pentium 4 and Athlon 64 should be comparable from a feature and performance standpoint, Intel and AMD will have to duke it out on the basis of pricing. Regardless of which manufacturer you prefer, extra features, speed, and lower prices are good for both you and your customers.