Tomorrow in New York, AMD will unleash its 64-bit AMD Opteron and AMD Athlon 64 processors, the company's most concerted efforts yet to steal market share from microprocessor giant Intel. Unlike previous AMD designs, the AMD Opteron and AMD Athlon 64 represent a technological breakthrough of sorts and don't simply ape Intel chip technology. Instead, the AMD chips provide a new 64-bit runtime environment that's completely compatible with today's 32-bit x86-based OSs and applications. But because the new processors are true 64-bit designs, a new generation of specially written OSs and applications will be able to take advantage of the increased memory space that a 64-bit address space offers.

AMD's approach to 64-bit computing contrasts sharply with that of market-leader Intel. Intel's completely new 64-bit design, the Itanium microprocessor, is incompatible with the x86-based software we use today. The Itanium provides an x86 virtual environment for some backward compatibility, but software running in the virtual environment does so slowly. Also, Itanium products are expensive and control only the most powerful 64-bit servers and high-end workstations. The AMD Opteron and AMD Athlon 64 will target enthusiasts, workstations, and low-end servers, and AMD will use PC-style pricing to ensure that the chips are widely available. And because the new chips are x86-compatible, systems based on them will run x86 software full speed, AMD says.

Contrary to popular belief, 64-bit microprocessors such as the Itanium, AMD Opteron, and AMD Athlon 64 don't necessarily run faster than 32-bit chips with similar clock speeds. Rather, the big advantage of 64-bit chips is a virtually unlimited memory address space, compared with the 4GB address space on most 32-bit systems. Itanium-based Windows Server 2003 systems, for example, can access as much as 512GB of RAM, and that limit is expected to grow in the coming years. The increased memory address space is especially important for massive databases, which can often run in RAM on 64-bit systems, dramatically increasing performance.

The AMD Opteron processor will likely become available within weeks, whereas the desktop-oriented AMD Athlon 64 should ship this fall. If AMD is successful, its new processors will finally usher in an era of 64-bit computing, which, although inevitable, seems to be somewhat stalled due to lackluster adoption of the Itanium. The PC industry made two previous major architectural leaps, from 8/16-bit computing to true 16-bit computing when Intel released its 80286 processor, and from 16-bit computing to 32-bit computing when the company released the 80386. Intel's 486, Pentium family, Celeron family, Xeon family, and Pentium M processors have all been 32-bit designs.

Key to AMD's success, of course, is software support, and Microsoft has pledged to release new 64-bit versions of Windows 2003 and Windows XP that run on AMD's new chips. Beyond that, little is known, though AMD should have some announcements at the product's launch Tuesday. So far, the company has simply said that it expects to see entertainment and gaming software titles take advantage of the technology.

In what is no doubt a purely coincidental move, Intel announced this weekend that it's cutting the prices on its fastest 32-bit chips by as much as 38 percent. The 3GHz Pentium 4 now costs $401, down 32 percent from $589, while the 2.4GHz version is now available for $348, down 38 percent. A newer version of the 3GHz Pentium 4, which uses a faster system bus and RAM than other Pentium 4 designs, costs $417; Intel introduced this chip last week but delayed its release because of a small technical glitch that the company hopes to resolve soon.