Rebirth for the x86

Once considered the weaker sibling of RISC processors, x86 chips are being re-architected with multi-core processors and 64-bit extensions that promise to extend their enterprise usefulness.

Your basic everyday x86 server doesn’t look so average anymore. In fact, with 64-bit extensions on the table and multi-core processors in the works, this venerable PC server is looking downright jazzy.

The x86 rebirth buzz began with Advanced Micro Devices’ (AMD) and Intel’s move to add 64-bit support to their processors. The 64-bit extensions show up in AMD’s Opteron and Intel’s Xeon chips. But it grows significantly louder when you throw in the multi-core angle.

Essentially, a multi-core processor gets you two processors on one chip. IBM, for example, offers a dual-core Power5 processor, while Sun has released a dual-core UltraSparc chip. PC vendors are not to be outdone. AMD is developing multi-core processors for servers and high-end workstations, and Intel recently moved up plans to ship dual-core processors for its server and desktop systems. Intel’s and AMD’s offerings are expected in late 2005.

The core issue

Although it will take years before multi-core designs become pervasive, the fact that they typically are designed to run at lower frequencies that burn less power than the latest single-core processors eventually will make data center servers denser than today’s single-core systems, says Tom Halfhill, senior analyst with Microprocessor Report.

“The whole idea of having two cores on one chip is that they are more efficient. For the same amount of data center square footage, you can have more processing power crammed in,” he says.

But vendors must resolve the thorny issue of software licensing before dual-core processors will achieve mainstream acceptance. As far as applications or the computer’s operating systems are concerned, a dual-core processor looks like a two-processor system. But should it be licensed as such? Not according to Scott Wolfe, IT enterprise architect with Boeing Employees Credit Union in Tukwila, Wash.

“We license Oracle per processor. . . . So now when we do dual cores, is that two processors?” he asks. “That dual-core processor is not as powerful as two single processors, so now we’re paying essentially twice the licensing for less than twice the computer power.”

Most vendors, including Microsoft and Novell, have not disclosed how they expect to treat multi-core processor licenses. However, the decision among those already decided on this issue is not uniform. A dual-core processor will be licensed as if it is two separate chips, as far as Oracle is concerned, but that same processor would require only one license from Red Hat.

While PC software vendors have some time to decide how they’ll handle licensing, Al Gillen, a research director at IDC, expects most will follow Oracle and license PC multi-core systems as if they are multiprocessor machines.

Perhaps the new systems will spur software vendors to reconsider their processor-based pricing models. That’s the hope of users like Dave Gallaher, director of IT development for Jefferson County in Golden, Colo. “At some point, I would have to call it the equivalent of counting the lug nuts on a car and using that as the basis of what you pay for the car,” he says. He advocates that software vendors move from this model and instead focus on one question in particular: “What’s the value of your product?”

An extended approach

With their 64-bit x86 extensions, AMD and Intel have created processors that, while 64-bit capable, also can run all of today’s 32-bit PC software out of the box. Because the additional 64-bit extensions, called AMD64 by AMD and Extended Memory 64 Technology by Intel, do not slow the performance of 32-bit software, customers have nothing to lose by adopting the new processors.

Intel and AMD intend to make their 64-bit instructions a standard part of their PC processor offerings. Both companies say the 64-bit extensions will be compatible with each other’s products, and with 32-bit x86 chips.

This means that the majority of PC server systems soon will be 64-bit-enabled, says Stuart McRae, manager of IBM’s xSeries line of servers. “In the first quarter of next year, virtually everything we ship will be 64-bit-enabled,” he says.

Gillen agrees: “By this time next year, you’ll be hard-pressed to find a 32-bit system.”

Still, the 64-bit software that will run on these chips is only beginning to emerge. Microsoft recently pushed back the release of a production version of Windows for 64-bit extensions until 2005, and vendors see no point in delivering Windows applications before the operating system is ready, analysts say.

For Linux users, 64-bit operating system support already is available from Red Hat and Novell’s SuSE Linux. But even on Linux, application support is still in the early stages. Support tends to be confined to open source products such as PostgreSQL and MySQL, and to high-performance computing applications.

Reducing the RISC

The advent of 64-bit x86 processors will go a long way toward eroding a primary advantage of 64-bit reduced instruction set computing (RISC) systems based on chips such as Sun’s UltraSparc and IBM’s Power processor.

Because 64-bit applications can process numbers with twice as many binary digits as their 32-bit counterparts, they can have the capacity to address a larger range of system memory. A 32-bit system can’t address more than 4G bytes of memory at a time. With 64-bit systems, this limit theoretically jumps to 16 billion gigabytes.

The maximum amount of addressable memory supported by IBM’s 64-bit Xeon systems today is 16G bytes, McRae says – far less than the theoretical maximum, but still four times that of 32-bit systems. While this change might not have any impact on an application like Microsoft Word, it will have a big effect on any application that needs to store large amounts of data in memory. Databases, e-mail servers, collaboration software and even access software such as Citrix Systems MetaFrame will benefit from the move to 64 bits, he says.

“Customers need to think about which applications are memory-intensive and which ones can get the most bang for the buck by moving to a 64-bit operating system. They’re going to get the hardware functionality whether they want it or not,” he says.

This is the final death knell for Unix, says Gallaher of Jefferson County: “Why would you really want to buy a big Unix box when you can have a big Linux box?”

Jefferson County already has switched much of its IT operations from HP-UX to Linux, and the county is now in the process of evaluating 64-bit systems based on Intel and AMD PC processors, he says. The county has 10 PA-RISC servers right now and will phase out two of them over the next six months, Gallaher says.

However, where the switch to Linux has really had an impact is in the new applications the county has added over the past few years. “We have not written an application to run on HP-UX in years,” he says. During that same time, the number of Linux machines at Jefferson County has risen from zero to 70.

For the $3,000 to $5,000 the county would spend per 64-bit PC server, Gallaher says he would get comparable performance from a RISC system that costs 10 times as much. Long live the PC processor.

McMillan is a reporter for the IDG News Service. He can be reached at robert_mcmillan@idg.com .