AMD's enchanted April

After years of hype, the AMD Opteron 64-bit processor will debut in April. The company and its shareholders might curse the rotten timing, but the current contracted market is actually the perfect setting for AMD's new technology. While other chipmakers scramble to adapt, AMD seems to have designed current business challenges and priorities into its architecture. Considering how long Opteron has been in engineering, AMD is either very smart or very lucky. Opteron may be an opportune solution for customers looking to consolidate their servers and reduce operating costs.

The advantages of AMD's new design are many. The most talked-about feature is the CPU's support for 64-bit applications. Unlike previous 64-bit processors, Opteron implements the full x86-32 instruction set. Software that runs on a Pentium III or AMD Athlon now will run unmodified on Opteron. Opteron-based servers will likely spend the majority of their time running the 32-bit Windows and Linux programs that businesses use today.

Software written to exploit Opteron's 64-bit capabilities will break through the barriers that prevent the x86 from running extremely demanding server and technical applications. A vastly expanded address space (up to 1TB of physical memory), a larger set of high-speed registers, and new instructions will take affordable servers to a higher level of performance. Running in 64-bit mode, an Opteron application can crunch through mountains of in-memory data and perform blazingly fast data transfers to network and storage devices.

Unlike other x86 processors, the Opteron CPU has the inherent ability to link up to eight processors without specialized chips. Every processor has three HyperTransport bus controllers for fast connections to other CPUs and devices. Instead of using an external memory controller, which complicates system design and adds latency, AMD links memory directly to each CPU. The design has plenty of headroom to accommodate faster memory and I/O devices. The only speed limit is the 19.2GB per second capacity of each chip's combined HyperTransport channels, which exceeds the top speed of the most capable PC server bus.

In systems that require more than eight processors, Opteron will rely on external chipsets to provide communications between CPUs. The fact that HyperTransport is already on the chip simplifies the engineering. Systems running two- and four-CPU configurations -- which account for most x86 server sales -- will ship in 2003. How soon larger systems appear depends entirely on market demand.

Answering critics

The chief criticisms leveled against the platform by Intel and critical analysts -- mainly that Opteron is immature technology and that Microsoft is dragging its feet porting Windows to it -- will prove groundless. The well-respected and thoroughly debugged Athlon x86 processor is the foundation of the Opteron chip. The remarkable HyperTransport bus that AMD uses to tie Opteron chips to each other and to I/O devices is already in widespread use. The DDR (double data rate) memory that AMD has chosen for its first implementation is inexpensive and readily available. AMD's chipset implements standard PCI-X and AGP (Accelerated Graphics Port) peripheral buses. System manufacturers and customers will have relatively few adjustments to make.