Intel Bites the Bullet: Xeon Gets 64-Bit Support

by Timothy Prickett Morgan

The conspiracy theorists are not always wrong. The future Xeon workstation and server processors from Intel that are based on the new "Prescott" core that was announced a few weeks ago do indeed have 64-bit memory extensions in them. With the launch of 64-bit Xeons, which will roll out in the next several months, server strategies based on Itanium and Opteron are put into a new light, if not called directly into question.

Intel made the announcement of the 64-bit extensions to the Xeon processors last week during the opening keynote address by CEO Craig Barrett at the Intel Developer Forum in San Francisco. In referring to the 64-bit extensions, which were reportedly developed under the code name "Yamhill," Barrett called the extended Xeon "probably the worst kept secret in Silicon Valley history."

It is easy to laugh about this, but Yamhill is serious business, and the fact that rival Advanced Micro Devices had garnered two tier one server suppliers with its 32/64-bit Opteron processors (IBM and Sun Microsystems) and looked as if it was just about ready to close the endorsement of a third (Hewlett-Packard) seemed to have forced Intel's hand. Intel would have undoubtedly preferred that the industry would have wholly supported its 64-bit Itanium alternative after investing a decade and billions of dollars in that product line. But to not extend Xeon would be to let the AMD camel gets its nose under the Intel circus tent. It is better to have three processor product lines than have your two products lose business to a rival alternative that has many of the same benefits embodied in one product.

Barrett's presentation, like so many of them at IDF in the past, focused on the increasing digitalization of the world and Intel's position as a key supplier of circuits that power the convergence of computers, communications, and content. These speeches are not so much broken records to the 5,000 attendees of IDF as they are a great song that they love to hear over and over. Rather than just dive right into the 64-bit Xeon announcement, Barrett started from the top of its product line with big iron Itanium chips and worked down to the desktop, PDA, and cell phone devices which have Pentium and Xscale processors. Before talking about the 64-bit Xeons, Barrett stressed that Intel had sold over 110,000 Itanium processors to date and that it would at least double that number in 2004. (It was not clear if he meant Intel would sell 220,000 or more additional Itaniums or double the installed base to 220,000.) He said that over 50 OEM partners were pushing Itanium machines and that over 1,000 applications have been ported to Itanium.

"Lots of new capabilities will be coming for Itanium," he said, including dual and multiple core implementations, chip multithreading, improvements in cache memory reliability, PCI Express I/O, and better power management features that allow the Itanium processors to run at a cooler temperature.

And to make his point that the Itanium processors have a long life ahead at Intel, Barrett brought out the CEO and CIO of Morgan Stanley, the financial services giant based in New York, to swear their loyalty to both Itanium and Xeon. In 2001, Morgan Stanley began a project to migrate away from its RISC/Unix back end database and risk arbitration systems (which were apparently based primarily on Sparc/Solaris iron) to X86 servers running Red Hat Linux. Morgan Stanley said that over the course of the past four years, when this migration was taking place, it had quadrupled its trading volume to 1 million trades a day, but the amount of fees it could extract from each trade had fallen by a stunning 80 percent. The only way to stay in business was to radically cut the cost of each transaction. And while 32-bit Xeon servers offer low prices, for the kind of number-crunching and big database jobs that Morgan Stanley is running, Itanium, not Xeon, provided the best performance and, ultimately, the best bang for the buck.

According to Jeff Birnbaum, CIO at the Morgan Stanley, on the risk assessment financial applications it runs, the Itanium outperformed the fastest Xeons by a factor of 2.5 times, thanks in large measure to the floating point performance of Itanium. On database applications, where main memory makes a big difference in performance, the Itaniums could outpace the Xeons on a chip-for-chip basis by a factor of 3 to 10 times running Morgan Stanley's actual code.

This, of course, begs the question of how the 64-bit support in Xeon will change the cost/benefit analysis at the thousands of companies like Morgan Stanley who have already adopted Itanium as well as at the many millions of companies who have not yet bought 64-bit servers but who will in the coming years. It is hard to fathom how much the expanded memory means to the performance of entry and midrange systems, but it is critical for any enterprise class system. To put it bluntly, any 32-bit system has a maximum of 64 GB of main memory it can address, and that is simply not enough in a box that might have 16, 32, or 64 processors in a single system image sharing that memory. For big iron, its was either Yamhill or Boot Hill for Xeons, because companies would either have to jump to Itanium or hope that Opteron machines would eventually scale beyond their current practical eight-way limit.

The important thing to IBM and Dell, neither of which are very ardent supporters of Itanium, is that 64-bit Xeons have finally been announced. Exactly what HP feels about all of this is unclear, but it must be torn by its desire to see Itanium turn to its own advantage and its desire to sell inexpensive iron and win deals against all other server makers. Sun already supports a 32-bit version of its Solaris Unix environment on Xeon chips, and has recently adopted the Opteron as its 64-bit Solaris X86 platform. It will be interesting to see what the advent of 64-bit Xeons means for Sun's long-term server strategy and its relatively new commitment to AMD.

Barrett said that the 64-bit extensions for the Xeon chips would ship first next quarter in the "Nocona" Xeon DP kickers to the current "Prestonia" Xeon DPs. The Noconas have the new Prescott cores that can access an 800 MHz front side bus, while the Prestonias have the older "Northwood" Pentium 4 cores. He also said that the 64-bit extensions to Xeon would ship in mid-2004 with the actual uniprocessor Prescott chips, and would debut in the high-end "Potomac" Xeon MP chips, which are aimed at four-way and larger machines, in early 2005.

It seems that the ability to access 64-bits in the Xeons will be determined by chipsets as much as by the chips. That means that the future "Grantsdale" chipset, which will begin shipping in the second quarter, is what really allows Prescott to do 64-bit computing. The Nocona Xeon DP chips are expected to support two chipsets, "Lindenhurst" and "Tumwater," dual-processor servers. It could turn out that while both chipsets will support PCI Express point-to-point I/O interconnections, DDR2 memory subsystems, and on-board dual Gigabit Ethernet links, one chipset could offer 32-bit processing on Nocona Xeon DP chips activated for 32-bit mode while the other chipset is for 64-bit mode Noconas. The different chipsets could turn out to be for workstation or server implementations and that they both support 32-bit and 64-bit modes. Either is possible. There only appears to be one chipset for the future Potomac chips, the "Twin Castle" chipset. That probably means that future Xeon DP and MP chips will be able to run in either 32-bit or 64-bit modes, like the Opterons can. This is what customers want.

The Nocona chip will run at 3.2 GHz, have 1 MB of L3 cache, and will sport an 800 MHz frontside bus. Nocona will be implemented in a 90 nanometer process, just like the Prescotts. The "Jayhawk" Xeon DP, due in late 2004 or early 2005, will be essentially the same chip, but with a higher clock speed and possibly a larger L3 cache. In mid-2005, Intel is expected to roll out a dual-core version of Potomac called "Tulsa," which will also plug into the Twin Castle chipsets. All five of these chips--Prescott, Nocona, Jayhawk, Potomac, and Tulsa--will support 64-bit processing.

Barrett said last week that over 5,000 developers, systems partners, and software partners have had access to the 64-bit Xeons and are working on ports and qualifications for their products. In a question and answer session following the keynote address, he said that the Intel Pentium and AMD Opteron processors had a different microarchitecture and therefore software written for one would have to be tweaked on the other. But it could turn out that Intel, which has a cross-licensing agreement with Intel, has simply implemented AMD's 64-bit methods from Opteron inside Xeon. In effect, 64-bit Xeons may turn out to be AMD inside. On the software front, Barrett said that Microsoft had been working for quite some time on the 64-bit Xeon support for Windows 2003, and said further that Red Hat, SuSE, and MonteVista Software would be rolling out versions of their Linux operating systems for the 64-bit Xeons. All four are expected to deliver their tweaked operating systems for 64-bit Xeons in the mid-to-late 2004 time frame.