AMD's Opteron UPS Ante Vs. Intel's Xeon

Appropriate for a time when IT budgets are tight, Opteron enables a gradual migration to 64-bit computing instead of a scrap-and-replace sale.

Opteron delivers 64-bit capability while remaining compatible with the vast quantity of 32-bit x86 software. In fact, 32-bit and 64-bit applications can run side-by-side atop a 64-bit operating system. Even on a 32-bit OS, Opteron enhances legacy applications' performance because of its wider data paths. There's no instruction translation layer or compatibility mode to limit the performance of 32-bit applications.

Other architectural advances allow Opteron to improve 32-bit and 64-bit performance. In a current Intel Xeon-based or an earlier AMD Athlon-based server, all CPU requests must pass through an external controller to access memory, which limits performance by introducing latency. Opteron designers changed that architecture by embedding a DDR memory controller on the die of each processor, so any application depending heavily on RAM will benefit greatly from the design.

Yet some skeptics question Opteron's embedded dual-RAM controller. If RAM is connected directly to each CPU in a multi-processor system, they say, what if the first CPU must access a piece of data in the memory controlled by another CPU? Isn't there extra latency? Well, not really. The hypertransport links between CPUs are designed to offer 6.4 GBytes per second of bandwidth per link, which eliminates the extra latency from one CPU to the other. In fact, the links are faster than the RAM access, the Test Center found.

Opteron also has hypertransport technology for communicating from chip to chip and then between the chips to the I/O chain. Hypertransport boosts overall system performance by removing I/O bottlenecks, increasing bandwidth and speed plus reducing latency.

With Opteron's hypertransport, solution providers and systems builders can offer a high-performing server. And AMD aims to prove that Opteron is powerful enough to compete with Xeon in the corporate space, which AMD has found difficult to penetrate.

Opteron already has won followers. Austin, Texas-based OEM Newisys, which specializes in server design, is so confident that Opteron will succeed that it plans to sell Opteron-based servers exclusively in the channel.

Test Center engineers evaluated the Opteron-based Newisys 2100 server. Priced at $7,999 and distributed by RackSaver, the product includes two Model 244 1.8GHz Opteron CPUs, two 36-Gbyte SCSI hard drives and 6 Gbytes of DDR2700 SDRAM.

And the Newisys 2100 isn't just a Pacific Rim motherboard thrown into a commodity chassis; Newisys designs its servers from the ground up. The motherboard, associated peripherals, cards, LCD control panel, legacy I/O, SCSI controller and power supply are blended into a cohesive package. In typical server setups, RAM capacity ranges from four to six DIMM slots. The Newisys 2100 box has eight DIMM slots, all validated for each module to run at 2 Gbytes. The ability to incorporate 16 Gbytes will offer a significant performance improvement to any application that can benefit from AMD's on-die memory controller and additional memory bandwidth and reduced latency.

When it comes to AMD processors, performance has always been a matter of architecture rather than clock speed. While it remains to be seen if Opteron will threaten Xeon's dominance on the network server, Web server or application server fronts, AMD's new server platform shows promise.