For years, my desk has been cluttered by two computers — one Macintosh and one PC. It's been an arrangement of necessity, as I prefer the Mac but sometimes need a Windows machine for work.

So it was with great interest that I read about Apple Computer Inc.'s (AAPL) launch last week of a program allowing newer Intel-based Macs to boot Microsoft Corp.'s (MSFT) Windows operating system. A day later, another company unveiled software that runs Windows in Mac OS X at nearly full speed.

In both cases, software emulation isn't required because the new Macs share the same hardware brains as Windows PCs. Unlike Microsoft's Virtual PC program that lets some Windows programs run on my old PowerPC-based Mac, there's no significant performance hit.

The major difference between Apple's Boot Camp and Parallels Software International Inc.'s Parallels Workstation is that the latter allows the user to seamlessly switch back and forth between the systems without restarting.

Boot Camp requires a decision at startup — if you want to run the other OS after that, you need to reboot.

To see which approach — Apple's dual booting or Parallels' Windows-in-a-window — works best, I installed them on a borrowed 20-inch iMac with a 2-gigahertz Intel (INTC) Core Duo processor. (They also run on other Intel Corp.-based Macs, including the MacBook Pro and the Mac Mini.)

It took each about 45 minutes to install the operating system, which must be purchased separately (Windows XP starts at $199). The process was simple for both programs — even though they're both labeled beta, or test, software.

Parallels Workstation's most obvious advantage is its ability to run both operating systems simultaneously. Most people probably would rather not restart their computer just because they need to access an application. The Windows OS runs inside a Mac window and users can easily and quickly switch back and forth between operating systems.

The system also automatically recognized the Mac's wireless Internet connection as well as the computer's wireless Bluetooth keyboard and mouse.

But Parallels Workstation does have significant flaws.

The program doesn't yet provide the native graphics drivers needed to make the display hardware run at full speed. That may explain the fairly significant drop-off in speed from a regular PC. Even moving the computer's cursor around the screen felt jerky.

After installation, I launched the program. But I quickly discovered that it wouldn't allow me to use the iMac's CD/DVD player to install Windows XP.

After several attempts to work around this, I found a solution: You need to insert the Windows XP CD into the computer before launching the Parallels Workstation program.

Within the Parallels Workstation environment, DVDs are not yet supported. The company plans to fix that in the next test release.

Still, Parallels Workstation — a free download while it is in beta but available for $49.99 in "a few weeks" when the company says it will be officially released — was a usable solution for occasionally running Windows applications. It should only get better with improved hardware support.

Apple's Boot Camp, which is available as a free download, feels much more like a finished product, despite its beta label.

Apple includes most of the hardware drivers needed to make the computer work. During the installation of Boot Camp, it walks you through the process of installing the drivers to a CD, which you'll use after the Windows installation is complete.

Performance is what you would expect running Windows XP on a similarly configured PC.

Even hardware that the company claims wouldn't work within the environment, such as the Bluetooth wireless keyboard and mouse, ran perfectly in the Windows OS. (The initial setup, however, required a wired keyboard and mouse.)

The only hardware that I found didn't work was the iMac's built-in video camera.

No Windows software tripped up Windows XP via Boot Camp. I installed my company's Virtual Private Networking client and the PC-only software used to write this story, and both worked — just as they would on a "normal" PC.

Windows games installed and played at top speed without a hitch.

Aside from the annoyance of having to reboot the computer to switch operating systems, the only complaint I had about Boot Camp is the Mac operating system's inability to take full advantage of the hard drive partition formatted to XP's default NTFS file system.

Macs can read NTFS drives. But the Mac operating system cannot write to them, making it difficult to share files across both environments.

Users creating PC disk partitions smaller than 32 gigabytes should stick to using the older FAT32 file system. Macs can read and write to that format.

Still, at the moment, it seems Apple's approach works best — if only because Boot Camp contains very few bugs, has almost complete hardware support and Windows XP runs as you would expect on a PC.

For hardcore gamers, there really is no option. Boot Camp is the best way to run Windows games on a Mac.

But for computer users who today need to use a few PC-only Windows applications, Parallels Workstation bears watching. If the company can develop graphics drivers and work out the kinks in the product, it could become the coveted all-in-one solution of the computer world.