Being something of a techno-junkie, I was anxious to get Windows XP Professional x64 Edition up and running on my desktop. I recently built a new desktop system using an AMD Athlon 64 3200+ processor, dual 150GB Serial ATA (SATA) drives, and 1.5GB of RAM on an ASUS motherboard that has NVIDIA's nForce chipset. The system also includes a DVD-ROM drive and Pioneer Electronics DVD burner. I didn't go out of my way to build in 64-bit compatibility, so I was interested in how the new 64-bit XP OS would fare on the system. Here are the 10 most interesting things I discovered about XP Pro x64 in the process.

10. There's no retail version—You can't simply go to your local computer store and purchase XP Pro x64—there's no retail version at this time. Unless you receive a copy as an MSDN or TechNet subscriber, you must acquire XP Pro x64 from an OEM partner.

9. Installation—Running the setup program was easy, but several peripherals, including the network card, USB ports, and audio, didn't work. Device Manager showed that drivers weren't installed. The ASUS installation CD had an XP x64 directory, but those drivers didn't work. Fortunately, I found a set of beta drivers for the motherboard that work fine at http://www.nvidia.com/object/nforce_udp_winxp64_6.25.

8. Device drivers—Finding 64-bit device drivers reminded me of the old Windows NT days. Using the default driver, the DVD burner could read but not burn DVDs. And, there were no native 64-bit drivers for my wireless Microsoft keyboard and mouse, although again the default drivers worked and provided basic functionality. One site that lists
64-bit drivers is http://www.planetamd64.com.

7. Running 32-bit applications—After I installed the correct motherboard drivers, the first thing I noticed about the system was how familiar it is. It looks and acts just like 32-bit XP. XP Pro x64 runs 32-bit Windows applications using the WOW64 subsystem, which lets 32-bit and 64-bit applications run side by side. Microsoft Office 2003 ran fine, as did most of the other 32-bit applications I was able to install.

6. Finding 64-bit applications—The OS can run 32-bit and 64-bit applications side by side, but 64-bit applications are still quite rare. A couple interesting exceptions are SiSoftware's Sandra 2005 system benchmarking software and Microsoft SQL Server 2005 Community Technology Preview (CTP) releases. More native 64-bit applications should appear within the next year.

5. No 16-bit subsystem—XP Pro x64 doesn't have the 16-bit DOS subsystem, but I didn't think it would matter. Surprisingly, however, several popular Windows applications, including Intuit's Quicken, still use 16-bit installers. The Cisco Systems VPN client I used was another unexpected casualty of the lack of a 16-bit subsystem.

4. Antivirus incompatibilities—Of the antivirus programs I tested, which included Symantec and McAfee products, none worked. But that will change soon—most antivirus vendors should be offering 64-bit solutions by the time you read this.

3. Third-party firewalls—Although the built-in Windows Firewall works just fine, third-party firewalls don't. During my testing, the only available third-party 64-bit firewall was the beta version of Computer Associates' (formerly Tiny Software's) Tiny Firewall 64. Again, I expect this situation to improve quickly.

2. VM software—The virtual machine (VM) software I use was also affected by low-level OS differences. Microsoft Virtual PC threw an "incompatible OS" error and wouldn't install. And I had to upgrade VMware Workstation 4 to the new Workstation 5 release to get 64-bit host OS support.

1. System performance—I expected sparkling performance, and I wasn't disappointed. I'm a multitasker, typically running 10 to 20 applications concurrently, and this system does a much better job of accommodating my work habits than my old 32-bit desktop did. Although the performance improvement was likely due in part to the wider code path available on the 64-bit platform, it probably also benefits by XP Pro x64's use of the Windows Server 2003 Service Pack 1 (SP1) code base.