Up Front : 64-Bit PCs: The Long and Winding Road

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Funny thing about technology revolutions: They're almost always more evolutionary than revolutionary. With PCs, change is a given, of course. But it tends to come in bits, pieces, fits, and starts.

Case in point: 64-bit computing, the revolution-in-the-making that Paul Thurrott covers in "XP Goes to 64 Bits," this issue's lead News and Trends story. The 32-bit PC platform is almost two decades old now; for years, it's been clear that far more potent 64-bit technology will eventually supplant it. The only uncertainties have been nitpicky little questions such as how, when, and why.

Until lately, the road to 64-bit has felt like a series of dead ends. Way back in 1998, for instance, PC World wrote about satisfied users of Windows computers built around the 64-bit Alpha processor, and yet the Windows/Alpha platform quickly died. More recently, Itanium, Intel's first foray into 64-bit CPUs, has languished.

AMD's Athlon 64 processors, however, are the real deal. Operating in both 32-bit and 64-bit modes, the Athlon 64, which debuted in late 2003, is fully compatible with software written for x86 processors such as the Pentium 4. That's a key advantage over earlier 64-bit CPUs, which required all-new operating systems and apps.

Even in 32-bit mode, the Athlon 64 is one fast CPU. Small wonder, then, that systems based on it regularly land on our "Top 15 Desktop PCs" chart.

Later this year, those machines are likely to be joined by ones that use new Intel processors that also run in both 32-bit and 64-bit modes (see our report, "Processors: Intel, AMD Plan New 64-Bit Desktop CPUs"). The Apple platform is following a similar path: A G5 Macintosh is a 64-bit system that runs the 32-bit Mac OS X.

Among the applications that will benefit most from 64-bit power are video editing, DVD authoring, heavy-duty database work, and 3D gaming. All will reap rewards from 64-bit CPUs' ability to address massive amounts of RAM--theoretically up to 16 billion gigabytes of the stuff. "If you need more memory, 64-bit will be a godsend," predicts Nathan Brockwood, principal analyst at research firm Insight64. For now, though, it'll be a pricey one: 4GB of RAM still costs upwards of $1000.

Waiting for Windows

Even with plentiful RAM, a 64-bit PC running a 32-bit operating system and applications is a caged tiger: Very little of its potential is actually getting used. True, 64-bit Linux is available right now, but the vast majority of the world's desktops won't go fully 64-bit until Windows and the applications written for it do. That's why the upcoming Windows XP Professional X64 Edition--which Thurrott test-drove for this issue's story--is so important.

For most users, however, there will be more arguments against this upgrade than for it. For one thing, XP Pro X64's changes are strictly architectural. And though it will run most 32-bit programs, most of the 64-bit apps designed to unleash its power won't show up for awhile. X64 will require new peripheral drivers, too; some won't appear right away, and others may never get written at all.

But even if you don't dive into Windows X64, developers will, as they get to work on 64-bit applications. Until now, "it's been a chicken-and-egg thing--the operating system needs to be out there," explains Brian Marr, a Microsoft senior product manager. By 2007, though, all of the pieces of the puzzle could be in place to support full-blown 64-bit computing.

Sound like a long wait? Even then, the transition won't be complete. For example, Longhorn won't be exclusively 64-bit; there will also be a 32-bit version. "The 16-to-32-bit change took a good ten years," muses Tom Halfhill, senior analyst at Microprocessor Report. "You have to think it's going to take another five years before [64-bit computing] is ubiquitous."

As I said, tech revolutions tend to take their own sweet time. But the best ones are worth the wait. We'll keep on monitoring 64-bit's progress in these pages--and we hope you'll be along for the ride.

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