Virtualization: Windows on a Mac

The best way to run Windows on your Mac

Today's Best Tech Deals

Picked by Macworld's Editors

Top Deals On Great Products

Picked by Techconnect's Editors

Despite the Mac's recent gains in market share, Windows is still the dominant operating system, especially in businesses. That means there may be times when you need to run the Microsoft OS: perhaps there’s an application your company uses that’s only available for Windows, or you’re a web developer and you need to test your sites in a true native Windows web browser. Or maybe you want to play computer games that aren’t available for OS X. Whatever your reason for running Windows, there are a number of ways your Mac can do it for you.

If you need to run just one or two specific Windows apps, you may be able to do so using CrossOver ( ), which can run such applications without requiring you to actually install Windows. (CrossOver's vendor, CodeWeavers, maintains a list of compatible apps.)

If you need a more flexible, full-fledged Windows installation, you still have several other options. You could use Apple’s own Boot Camp, which lets you install Windows on a separate partition of your hard drive. Or you could install one of three third-party virtualization programs: Parallels Desktop 7 ( ), VMware Fusion ( ), or VirtualBox ( ), each of which lets you run Windows (or another operating system) as if it were just another OS X application.

Of those four options, Boot Camp offers the best performance; your Mac is wholly given over to running Windows. But you have to reboot your system to use Boot Camp, so you can’t use it at the same time as OS X; it's Mac or Windows, but not both. And while VirtualBox is free, setting it up is complicated—downright geeky, at times—and it lacks some bells and whistles you might want. Which leaves Parallels Desktop and VMware Fusion as your best alternatives.

So, of those two, how do you decide which one is right for you? In the past, I tried to answer that question by comparing virtualization programs head-to-head, to see how they did on specific tasks. This time, however, that task-based approach didn’t work, largely because (with a couple exceptions that are noted below) the latest versions of Fusion and Parallels Desktop are nearly indistinguishable in performance. So instead of picking one program over the other based on how well it performs a given task, the choice now hinges on some more subjective factors. So this time around, I’ll look at those and try to explain how the two programs differ on each.

Note that, for the most part, I've focused primarily on using these programs to run Windows on your Mac. You can, of course, use them to run other operating systems—including OS X Lion itself—but that’s not the focus here.

General Performance

As noted, both Parallels Desktop and Fusion perform well when it comes to running Windows 7 on a Mac. Macworld Labs ran both programs through PCWorld’s WorldBench 6 benchmark suite, and the results were close: overall, VMware Fusion beat out Parallels Desktop by a very slight margin (113 to 118, meaning Fusion was 18 percent faster than a theoretical baseline system, Parallels Desktop 13 percent). Parallels Desktop was faster than Fusion in some individual tests, Fusion was faster in others, and in the rest the differences were almost too close to call.

Parallels Desktop 7 vs. VMware Fusion 4

 Parallels Desktop 7VMWare Fusion 4
WorldBench 6 113 118
Adobe Photoshop CS2 377 328
Autodesk 3ds Max 8 (Service Pack 3) (DirectX) 340 307
Autodesk 3ds Max 8 (Service Pack 3) (rendering) 249 265
Firefox 2 253 246
Microsoft Office 2003 (Service Pack 1) 353 348
Microsoft Windows Media Encoder 9.0 175 177
Firefox and Windows Media Encoder (multitasking) 274 272
Nero 7 Ultra Edition 438 410
Roxio VideoWave Movie Creator 1.5 195 176
WinZip Computing WinZip 10.0 249 234

WorldBench 6 uses automated test scripts and eight different applications to simulate the real-world use of a system; we run the full suite multiple times then average the results together. For WorldBench scores, higher is better. All other results are in seconds; lower is better. Best result in bold. Tests run on a 2011 17-inch 2.2GHz Quad Core i7 MacBook Pro with 4GB RAM running OS X Lion 10.7.1; both Virtual Machines were configured to use a 200GB drive, 1724MB RAM, and 4 processors

Distill these numbers to their essence, and what you have are two fast, capable ways of running Windows on your Mac.

Advantage: Neither (or both).

Specific types of performance

While the two programs are practically indistinguishable in general usage, there are three specific scenarios in which greater differences emerge.

The first of them: gaming. If you want to run Windows in a virtual machine to play games that you can’t play on a Mac, then you’ll want to use Parallels Desktop 7. In my testing, it handily outperformed Fusion, especially on newer titles. One reason is that Parallels supports up to 1GB of video ram (VRAM), versus only 256MB in Fusion. Parallels Desktop also has better DirectX support; one game I tried looked fine in Parallels using DirectX, but awful in Fusion; switching to OpenGL in Fusion solved that problem, but not all games offer this option.

gaming performance
BMW Racing ran great in Parallels, with high frame rates and stutter-free audio.

Overall, Parallels Desktop’s 3D engine seems to work much better for games in Windows than does Fusion’s engine. So if Windows gaming is your thing, Parallels is the one you want to use.

Advantage: Parallels Desktop.

Linux with Accelerated Graphics

The second big difference between the two: Only Parallels includes accelerated 3D graphics in Linux virtual machines, so if you need that, you’ll need to use Parallels.

Advantage: Parallels Desktop.

Virtualization Explorer

The third big difference: If you want to explore operating systems other than Windows, Fusion offers a much broader universe of alternatives. Both programs support “virtual appliances”—dowloadable, pre-configured operating systems, often bundled with specific applications. VMware’s appliance library is huge, with over 1,900 appliances available; Parallels Desktop’ library, on the other hand, contains only 98. (Desktop can use VMware’s appliances, but they must first be converted to the Parallels format; it doesn’t really seem fair to give the program full credit for that capabiity, if it’s reliant on the VMware ecosystem.) So you want to explore the wild world of operating systems and applications, Fusion is the way to go.

Advantage: Fusion.

So much for the three categories with relatively clear winners; now for the more subjective criteria.

Purchase and license

Fusion and Parallels Desktop both normally cost $80, but pricing for both is a moving target. For example, VMware is currently offering Fusion at a promotional price of $50. Meanwhile, Parallels will sell Desktop 7 as an upgrade to owners of older versions for $50; if you’re currently using Fusion, Parallels will sell you Desktop 7 for $30. No matter how much you pay for a virtualization program, remember that you’ll also need to factor in the price of Windows itself.

There’s a big hidden cost in those prices: the software license. Fusion’s license (for non-business users) allows you to install and use it on any Macs that you own or control. Parallels Desktop, on the other hand, requires one license per machine, and it uses activation to check those serial numbers. So if you want to run your virtualization program on more than one Mac, Fusion will cost less—potentially much less.

Advantage: Fusion (for the moment).

Installation and general operation

Installing Fusion 4 is surprisingly simple: You just drag and drop the program to any directory you wish. There’s no installer to run, and you can store the program anywhere. When you first launch Fusion, it asks for your administrative password and activates its extensions. But those extensions aren’t hidden away in some low-level system folder where you’ll never find them. Instead, they remain within the Fusion application bundle and automatically activate on subsequent launches.

More importantly, they’re deactivated when you quit Fusion. In fact, when you quit Fusion, unless you choose to leave the Windows applications menu item in your Mac’s menu bar, absolutely nothing Fusion-related is left running. This setup also makes uninstalling a snap—just drag the app to the trash, and you’re done. Taking a program as complex as Fusion, and making it as easy to install and uninstall as any simple utility, is a major accomplishment.

Parallels, by contrast, is installed via an installer, its extensions are installed in the System folder and are always present, even when Desktop isn’t running. In addition, two background processes continue to run after you quit Parallels. These processes don’t take much RAM or CPU power, but they’re there.

Advantage: Fusion.

Preferences and virtual machine settings

Both of these programs have lots of settings options; Parallels Desktop has more of them and, consequently, has a more complicated preferences screen. Both of their preferences panels are reasonably well organized, doing a decent job of categorizing the various settings. One thing I don’t like about Parallels is that it automatically enrolls you in the company’s Customer Experience Program, which collects anonymous usage data; you have to opt out by disabling it in the Advanced section of Preferences. Fusion offers a similar program, but you have to opt in, not out.

preference panels
Fusion (left) and Parallels (right) take slightly different approaches to their preferences windows.

When it comes to changing the settings for a virtual machine, the two programs take a slightly different approach: Parallels Desktop uses a floating window that’s independent of the virtual machine being configured; that makes it easy to toggle between the settings and the virtual machine, but it’s also easy to lose track of the settings window if you click another window to the foreground.

Fusion, by contrast, dims the virtual machine, and presents a fixed window in the center of the screen, on top of the virtual machine. Its settings window mimics that of System Preferences, while Parallels uses a tabs-and-lists layout. Some users may prefer one over the other, but I find they both work reasonably well.

Advantage: Neither (or both).

Windowed windows

Both programs can be run in an “integration” mode, meaning Windows applications aren't bound inside a single Windows window; rather, they appear side-by-side in the OS X graphical user interface with Mac programs. (VMware calls this mode Unity; Parallels calls it Coherence.)

In this mode, both programs seem to treat these windows as though they're regular Mac apps. But there is a subtle but telling difference: Parallels Desktop actually treats the windows of your Windows apps as one, even though they display separately. You can see this if you activate Mission Control in OS X Lion: Regardless of how many Windows applications you’re running, they’ll all be lumped together in one Parallels Desktop entry. This means, among other things, that if you use a window-management utility, it may not work correctly.

Windows windows
Fusion (left) and Parallels (right) treat Windows apps' windows differently when running in their respective integrated modes.

Fusion, on the other hand, treats each Windows app like a window from any OS X application: The system treats them as truly separate from one another. If you open Mission Control while you’re using Fusion, each running Windows app gets its own entry.

If you prefer to think of your virtual machine as a single entity, you’ll probably prefer Parallels Desktop’ Coherence mode. But if you’re going to the trouble of using an integrated mode, chances are you want your Windows apps to behave just like your Mac ones. And in that case it makes more sense to treat the windows the way Fusion does.

Advantage: Fusion.


Programs of this complexity require frequent updates; there’s just so much going on that there’s always going to be another feature to add or another bug to fix. The two companies handle updates differently, however. Parallels Desktop pushes out updates rapidly, so users get the latest features and fixes as quickly as possible. Fusion has a slower update cycle. Both programs have in-app updating now, so that portion of the routine has gotten simpler than it was in the past.

So which update methodology is better, frequent small updates or occasional larger updates? That's really up to you; some people like knowing that they’ve always got the latest bug fixes and features, while others may prefer longer periods between updates. The important thing, though, is that both companies do actively keep their products up to date.

Advantage: Neither (or both).

And the winner is…

So which virtualization solution should you purchase? In my comparison, Fusion comes out ahead (four wins, two losses, and three ties). But you may prioritize these features differently than I do. That’s why I suggest you download each program’s free trial version and see how each handles your particular needs. Both are excellent performers in the Windows arena, so you won’t be disappointed by either program’s speed. Instead, your selection will come down to your feelings about those other, less measurable factors—and for that, nothing beats hands-on experience.

Senior Contributor Rob Griffiths is master of ceremonies at Many Tricks Software.

[Updated 02/14/12 to clarify the number of apps that can be run under CrossOver.]

Note: When you purchase something after clicking links in our articles, we may earn a small commission. Read our affiliate link policy for more details.
At a Glance
Shop Tech Products at Amazon