You may need (or want) to run Windows, or other operating systems, alongside your Apple Mac's Mac OS X, and Parallels Desktop is the best-known of several programs on the market for that purpose.

(Full native Windows support, of course, is also available via Apple's Boot Camp, but it requires you to reboot out of OS X and into Windows.)

A new-to-the-Mac player now brings a formidable challenger to the arena, however. VMware, an expert in x86 virtualisation — that is, the ability to run one or more x86 operating systems as "guests" under a "host" x86 operating system—has released Fusion 1.0, its first OS X offering. Like Parallels, Fusion allows you to run many versions of Windows and other operating systems from within OS X. And unlike Boot Camp, you don't have to log out and restart in order to use it.

VMware Fusion supports more than 60 operating systems: Windows coverage extends from version 3.1 to betas of Windows Server 2008. If Linux is your cup of tea, you'll find support for Red Hat, Ubuntu, SUSE, Mandrake, and more. You can also install Novell Netware, Solaris 9 or 10, FreeBSD, and MS-DOS systems. Even 64-bit releases of Windows and some families of Linux, such as Red Hat and SUSE Enterprise Linux, are supported.

As a Windows machine

Fusion runs Windows quite well - we tested it with Windows XP Pro and Windows 2000. Fusion also supports Vista, although some features (such as Unity and driver support) aren't fully functional with that OS. Given that Vista is still relatively new, this isn't surprising.

One of the key factors that differentiates Fusion from Parallels is Fusion's ability to use two CPU cores within a virtual machine; Parallels can't, and this makes a big difference in the performance of CPU-intensive tasks. It also seems to pay off by giving you a generally more responsive Windows experience.

Fusion has an Easy Install mode for Windows Vista, XP, and 2000. We tested this with a fresh XP Pro installation, and it worked perfectly — installing Windows in a virtual machine via Easy Install is actually easier than installing Windows on an actual Windows PC.

After Windows boots for the first time, you need to install VMware Tools on top of it using the Virtual Machine: Install VMware Tools menu item. This package improves graphics performance, adds support for shared folders and drag-and-drop, automatically grabs and releases the mouse pointer when in the virtual machine, and much more. VMware Tools can (and should) be installed on top of both Windows and Linux virtual machines.

Other paths to Windows

You may already have Windows installed on your Mac via either Parallels or Boot Camp, and Fusion will let you use either (or both) of those installations as Fusion virtual machines. Setting up your Boot Camp partition as a Fusion virtual machine is quite simple, and it worked perfectly in our tests.

We weren't asked to reactivate Windows again, although some users have reported this problem. To avoid this and other issues, make sure you follow the instructions in VMware's help documents (Help: VMware Fusion Help, then search for Boot Camp) exactly as they are written.

The process of converting a Parallels virtual machine is more complicated. You'll need to read the instructions in the Converting a Parallels Virtual Machine to Run in VMware Fusion PDF file, which you can download from the VMware site. We worked through the conversion process (including adding multiple CPU support), and while it took about an hour to process our 10GB Parallels virtual machine on an Apple Mac Pro, it did work as described.

The process isn't overly complicated, but there are a number of steps to follow. When it's done, you'll have your Parallels Windows installation up and running in Fusion, with the exact same programs and files as you had in Parallels.

Performance and usability

We tested a number of standard applications in Fusion, including Office 2007, Adobe Reader 8.1, Firefox, Apple's Safari 3.0.3 and QuickTime 7.2, Windows Media Player 11, and the Trillian Basic 3.1 chat program.

Office 2007 ran just fine, and we were even able to open and run one of our Mac Office 2004 Excel spreadsheets with embedded macros — something that we won't be able to do in the upcoming Mac Office 2008, as Microsoft will drop macro support from the Mac version of Office.

Adobe Reader, Firefox, Safari, and Trillian all ran as expected—compatibility in Fusion with typical Windows applications such as these is excellent. The programs load quickly, are stable, and work as well as they do in a native Windows environment.

Video playback in Windows Media Player, even using high-definition demo clips from Microsoft, was smooth. We had a bit of trouble with audio lag and skipping in a few of the QuickTime video clips, but they were generally still easy to watch.

We were also able to use the DVD burner on the Mac Pro to add files to a CD-RW disc, and the iSight camera works, so long as you install the iSight drivers from Apple's Boot Camp Windows drivers disc.

Fusion also supports some 3D games, though the support is limited to older DirectX 8.1 games. Fusion's release notes list only 11 supported games, all much older than the 40 or so listed on Parallels' site. (Fusion 1.1, now in beta, will add support for DirectX 9.0, which should expand the list of supported games.) We were able to find and run demos for a few of the games on the list, and they worked reasonably well - a steering wheel worked in the driving games, for instance, although the force feedback did not. If you really want to play games on your Windows Mac, though, Apple's Boot Camp provides the best performance.

Fusion includes excellent USB 2.0 support, so you shouldn't have any trouble with most third-party devices — not even products such as GPS receivers and Windows Mobile phones. We weren't able to get a Wacom tablet working in the Windows XP virtual machine; a search of the VMware forums revealed that this is a known issue.

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Other features

Fusion's Unity mode intermingles and fully integrates your Windows applications alongside your OS X applications. Any open Windows window becomes an independent, fully drop-shadowed OS X window — and running Windows applications have their own dock icons.

Fusion supports Windows XP in Unity mode, and has experimental support for Windows 2000, Windows Server 2003, and Windows Vista—meaning that you might see some visual glitches if you try to use Unity with one of those operating systems. Unfortunately, Unity only supports one monitor, so you won't be able to drag your Windows windows onto a second screen. There's no Start menu like the one you get with Parallels' analogous Coherence mode; instead, you use a floating Launch Applications window, and the Applications menu mimics most, but not all, of the Start menu's features. (Fusion 1.1 will optionally show the Start menu and task bar in Unity mode—though this option is off by default.)

Fusion also lets you create snapshots of your virtual machines, which makes it simple to undo changes. Take a snapshot before you install a program, for instance, and you can then revert to that snapshot via the menu if you decide you don't want that program installed. Unlike Parallels, which accommodates multiple snapshots per virtual machine (allowing you more flexibility to work in stages), Fusion permits just one.

Sharing files between the Mac and the virtual machine is quite simple, too. You can create shared folders that are visible within Fusion, or you can (at least with Windows virtual machines) simply drag-and-drop files between the Finder and the virtual machine, and vice-versa.

Fusion can run multiple virtual machines with much less RAM usage than you might expect. It does this by sharing the RAM that's used for identical features among the opened virtual machines. So if you're running two different Windows XP virtual machines, much of the RAM is shared, saving memory for additional virtual machines. In practice, we were able to run three Windows virtual machines and a Fedora Core Linux virtual machine simultaneously on our 4GB Mac Pro without running into any notable slowdowns.

Finally, Fusion tries to minimise its impact on native OS X applications, so that you won't see slowdowns in Pages, for instance, because your Windows XP Outlook is busy checking your email. We ran many OS X programs alongside Windows apps in Fusion, and never noticed any problems.

Run many different systems

Fusion supports VMware's Virtual Appliances, ready-to-run virtual machines, many of which can be downloaded and installed free of charge from a library of nearly 600 different choices. If you've ever wondered what it might be like to run Linux, Virtual Appliances are a great way to take a test drive. For instance, the Fedora 7 Virtual Appliance, can be downloaded, expanded, and then opened—and presto, you're running Fedora Core, with no installation required.

Help and support

While VMware has many enterprise customers, Fusion is clearly targeted to consumers. Unfortunately, support options are somewhat limited. Your purchase includes 30 days of free online support that covers installation as well as help using the VMware Converter to convert your Parallels virtual machines.

There's also extensive help available via the application's Help menu. The help file loads in your browser, but it includes a full table of contents, index, search feature, and the ability to mark certain sections as Favorites for easy future reference.

Online, you'll find a free knowledge base and the VMware forums. The forums have a lot of good information, and both users and VMware employees often answer questions quickly. There's also a free (registration required) collection of Fusion training videos that cover topics such as converting Parallels virtual machines, using USB storage and iSight cameras, printer setup, and more. If you need additional support, you can buy per-incident email support. Various additional onsite support plans are available for business customers.

Email support was prompt (VMware lists a response time of no more than 24 hours) and useful, and the support staff resolved an issue we had with the VMware Converter.

Both Fusion and Parallels have their strengths and weaknesses when it comes to support. Parallels offers unlimited email support, but response time may be slow, and telephone support is expensive. Fusion has a very good manual, training videos, and a strong community forum, but there's no telephone support.

Overall, as with Parallels, you may find that it's often faster and cheaper to use the web and your favourite search engine to find answers to your problems.

Fusion 1.0: Specs

  • An Intel-based Mac (to run 64-bit operating systems, an Intel Mac with a Core 2 Duo or Xeon processor is required)
  • 512MB of RAM (1GB or more recommended)
  • 275MB free disk space for VMware Fusion
  • 1GB free disk space for each virtual machine (10 GB or more recommended)
  • Mac OS X version 10.4.9 or later
  • An Intel-based Mac (to run 64-bit operating systems, an Intel Mac with a Core 2 Duo or Xeon processor is required)
  • 512MB of RAM (1GB or more recommended)
  • 275MB free disk space for VMware Fusion
  • 1GB free disk space for each virtual machine (10 GB or more recommended)
  • Mac OS X version 10.4.9 or later


Fusion 1.0 is a viable competitor to Parallels, and for consumers, that's a good thing. Already, the release of Fusion has inspired an incremental upgrade in Parallels so that its Coherence feature more closely matches what you get with Unity—and there's the upcoming Fusion 1.1 that will add better 3D graphics support, improvements in Unity mode, support for the Eject key, and a host of other improvements. We found Fusion easy, fast, stable (we had no hard lockups during my testing), and very well thought out. Its game support doesn't match that of Parallels, but if you're serious about gaming in Windows, you're not going to be using either of these programs anyway. Although it's a very close call between these two excellent virtualization programs, we prefer Fusion for its low impact on other OS X applications, support for multiple virtual CPUs, and huge library of virtual appliances.