An all-64-bit-computing world just took a significant step forward, and your upgrade path to that world just got a lot less risky. Why? Intel's new Xeons and future Prescott-based CPUs will support the same 64-bit software as AMD's existing Athlon 64 and Opteron chips. And like those AMD chips, the new Intel CPUs will continue to support your favorite 32-bit apps, as well. Another potential selling point for early adopters: If Intel follows AMD's lead in terms of pricing, you won't have to pay much--if any--premium for better-performing 64-bit desktop systems over comparable 32-bit-only PCs.

Because these Intel and AMD 64-bit chips will run the same OS and apps, development of software to take advantage of such chips--especially their ability to address larger amounts of system memory--should be faster, says Peter Glaskowsky, editor in chief of Microprocessor Report. "This eliminates the last bit of confusion for the application developers," he adds.

By moving to include 64-bit support in more mainstream x86 CPUs, Intel has abruptly altered its often-repeated position that only large servers--such as those using its pricey Itanium chip--currently require 64-bit capabilities. It's a public about-face that executives at longtime underdog AMD clearly relish. Meanwhile, that company expects its 64-bit-capable processors to make up 50 percent of its sales before year's end.

Does this mean your next purchase must be a 64-bit PC? Not necessarily, says Martin Reynolds, a vice president at research firm Gartner Dataquest. The lack of 64-bit apps could delay broad acceptance of 64-bit servers for a year, and 64-bit desktops won't hit the mainstream until after that, he predicts.

Which is why Intel has made no specific desktop announcements. It is waiting for drivers and OS support to arrive first, says Intel spokesperson George Alfs.

Full driver support won't be widespread for some time, but Microsoft will launch a 64-bit version of Windows XP later this year. Still, most analysts point to Longhorn--due in 2006--as the likely crossover point for 64-bit desktop computing to hit the mainstream.