On April 9, 2003, Microsoft officially announced that it would support AMD's then-upcoming 64-bit Opteron and Athlon 64 microprocessors with 64-bit native versions of Windows XP and Windows Server 2003. The news must have sent shivers down the spines of executives at Microsoft partner Intel, whose 64-bit Itanium product line has languished because of slow performance and incompatibilities with today's existing 32-bit software. For AMD, of course, it was--and still is--a major victory. Not only was the one time microprocessor also-suddenly getting equal press from Microsoft as Intel, within a year, Intel shocked the world by announcing that it would essentially ape AMD's designs and create 64-bit versions of the Xeon and Pentium 4 CPUs that would be code compatible. The follower had suddenly become the leader.

The beauty of AMD's 64-bit processor design, of course, is that it offers the best of both worlds. Based as they are on the 32-bit x86 architecture, the processors are completely compatible with all of the software and operating systems people run today. And unlike the Itanium, it can run those systems at full speed (or better than full speed, if recent benchmarks are to be believed). But the AMD64 platform, as it's come to be known, also offers all of the benefits of 64-bit computing: Primarily, a much wider address space that make it possible to build PCs, workstations, and servers that offer oodles of RAM. Today's 32-bit processors are (essentially) constrained to supporting just 4 GB of RAM, a figure that seemed massive 10 years ago. However, 64-bit versions of Windows will support a 16 terabyte (16 TB) address space. Today's 64-bit systems, of course, are limited by their physical designs, and offer less actual memory support. But 32 GB 64-bit systems are becoming common today, perfect for database servers, 3D graphics work, and other high-end uses.

Few people would doubt that the future of computing is 64-bits. But the slow uptake of the Itanium, in both the server and workstation markets, left market leader Intel with precious little to offer customers. However, the two previously mentioned events marked an unprecedented tilt in the history of the PC industry: AMD released an x86-compatible 64-bit line of microprocessors, and Microsoft elected to support it with its best-selling workstation and server operating systems. The 64-bit computing future, it seemed, would be coming sooner than expected.

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