January 16, 2012, 8:58 PM — 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 just a single Windows app, you may be able to do so using CrossOver ( Macworld rated 3 out of 5 mice ), which can run such applications without requiring you to actually install Windows.
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 ( Macworld rated 4 out of 5 mice ), VMware Fusion ( Macworld rated 4 out of 5 mice ), or VirtualBox ( Macworld rated 3 out of 5 mice ), 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% faster than a theoretical baseline system, Parallels Desktop 13%). 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.
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.
