Windows XP Professional x64 Edition

There's no question about it: 64-bit computing is the future, because it promises better performance and room to grow for memory-hungry applications and operating systems. In fact, millions of people already use desktops and notebooks with 64-bit processors that have been available from AMD since 2003 and Intel since February 2005. With the release of Windows XP Professional x64 Edition and Windows Server 2003 x64 Edition, Microsoft takes a big first step toward a 64-bit world. But Rome wasn't built in a day, and Microsoft's transition to 64-bit will be a gradual one. Windows XP Professional x64 Edition is not available in boxed editions via resellers; it will be sold only through OEM vendors and licensing agreements. The new OS is priced the same as the 32-bit Windows XP Professional, and for a limited time, current XP Professional customers running 64-bit systems can upgrade for free.

Microsoft can afford to take a measured approach to 64-bit computing because few software applications are available in 64-bit editions, and many hardware devices don't yet have compatible drivers. In fact, many of the native applications in Microsoft's new OS, such as Outlook Express and Windows Media Player, still run in 32-bit mode. Windows XP Professional x64 Edition is a big deal for software developers because it gives them a solid Windows platform to write programs that can harness the potential of 64-bit. The release also represents a major milestone toward Microsoft's next-generation Longhorn operating system. Windows XP Professional x64 Edition promises substantial speed improvements with CAD/CAM, 3D modelling, and other high-end tools that will justify the move to the new OS. For the average user, though, 64-bit Windows is, for now, little more than a curiosity. Compatibility issues far outweigh any potential speed boosts, making it an inadvisable upgrade for all but the most die-hard enthusiasts.

Setup & interface
If you already have one of the millions of 64-bit-capable desktops or notebooks running 32-bit Windows and want to switch, be prepared for headaches. Windows x64 doesn't offer a 32-bit Windows upgrade option; you'll need to do a fresh install. That means booting your system from the installation CD and navigating through some confusing text prompts to install the system. If you're planning to upgrade from a 32-bit Windows computer, you'll have to copy your settings (we recommend storing an image of your existing hard drive on an external hard drive) and reinstall all of your utilities and applications later. Although most of your applications will work fine within Windows x64's 32-bit compatibility mode, if the software includes its own device driver, you may encounter difficulties. For instance, when we tried to install iTunes, we were greeted with an error message saying that one of the drivers included with the software wasn't compatible with Windows x64. The application launched and appeared to work, but there's likely to be a compatibility issue lurking below. In addition, each piece of hardware in your system needs a 64-bit driver to work properly. Although Microsoft includes many common device drivers with Windows x64, older or less common pieces of hardware won't work without a driver supplied by the manufacturer. Vendors such as Brother, Canon, Epson, Lexmark, Ricoh, Samsung, Wacom, Xerox and Zoran currently offer driver support for the new OS, with other vendors expected to do so by the end of this year. By far the easiest way to get 64-bit Windows is to purchase a new system with the software preinstalled. That way, you're assured that all of the PC's hardware will have 64-bit drivers available. Acer, AlienWare, Dell, FSC, Fujitsu, HP, Hitachi, IBM, NEC and Unisys are expected to ship servers and workstations with either the server or workstation version of Windows x64 preinstalled. If you choose to upgrade a 64-bit system running 32-bit Windows XP, however, we strongly recommend creating a dual-boot system and installing Windows XP Professional x64 Edition onto a separate partition to test whether your hardware and software are compatible. Microsoft designed its new OS to be backward compatible with 32-bit applications, and that's good since much of the software bundled within Windows x64, such as Outlook Express and Windows Media Player, remain 32-bit. The big exception, however, is Internet Explorer (IE): Windows XP Professional x64 Edition includes both a 32-bit and a 64-bit version of the Web browser. However, since few if any browser plug-ins or toolbars are currently 64-bit, you'll probably want to use the 32-bit version for your daily Web surfing. At this time, there is no compelling reason to use 64-bit IE. Even Microsoft's own Windows Update is 32-bit only. When we tried using the Windows Update button on the Control Panel, Windows initially launched a 64-bit browser, and then redirected us to run Update in a 32-bit browser instead.

Features
Visually, x64 Windows differs little from 32-bit Windows XP Pro; the big changes are internal. Microsoft reworked the Windows XP Professional interface to run in 64-bit mode. In addition, x64 Windows is actually based on the Windows Server 2003 Service Pack 1 code base, which Microsoft touts as having better reliability and stability than its desktop versions of Windows XP. Because the new OS runs on 64-bit systems, you can now take advantage of a feature first introduced in Windows XP SP2, the so-called Data Execution Prevention (DEP) feature, sometimes referred to as No eXecute (NX), which combats viruses and worms attempting to take advantage of buffer overruns in your system's memory. And because there are very few 64-bit applications, your current 32-bit applications run in a separate protected memory space to ensure compatibility and reliability. The main advantage of a 64-bit operating system comes in its ability to handle huge amounts of memory. Thirty-two-bit Windows is limited to 4GB of physical RAM, with only 2GB available to an application, although there is a workaround that lets some applications access up to 3GB. Sixty-four-bit Windows blows away this limitation, supporting up to 128GB of physical RAM and 16 terabytes (TB) of virtual memory. Of course, most systems don't have close to 2GB of RAM, and even if yours did, the extra memory wouldn't come in handy when accessing your bank account or downloading MP3s. Microsoft designed Windows XP Professional x64 Edition for workstation applications such as CAD/CAM, 3D modelling and scientific simulations, where extra memory support promises a big boost in performance. For example, instead of storing data on the hard drive, active applications will be able to store everything in much-faster RAM instead. Even without massive amounts of memory, applications currently optimised for the 64-bit architecture may also see a speed boost as they take advantage of the processor's full capabilities. This could extend the performance boost to areas such as 3D gaming and video, sound and photo editing. However, it will take a while until most popular applications are optimised for 64-bit. Vendors such as Avid, Softimage, BEA Systems, BMC, Cakewalk, Citrix Systems, CommVault, Computer Associates, IBM, McAfee, NewTek, Oracle, PTC, Symantec, Trend Micro and Veritas Software have or will soon announce 64-bit editions of their software. More vendors are expected by the end of the year.

Service & support
We expect technical support for Windows XP Professional x64 to include email and some answers on an online FAQ page. Phone support is available (at National Rate, typically 8p a minute) between 8am and 6pm Monday to Friday.