Since I last reviewed VirtualBox, the application has gone up one version number (from 2.1 to 3.1). In the process, it has acquired some substantial new features, including better support for multiple virtual CPUs and DirectX 8/9 (when you're running Windows); I dinged the last version of the program for its lack of both.
In addition, VirtualBox 3.1 supports OpenGL 2.0 in Windows, Linux and Solaris operating systems. It also has a new toolbar in full-screen mode, a redesigned settings interface, and a number of low-level changes and bug fixes.
To put VirtualBox through its paces, I installed Windows XP Pro, Windows 7 Ultimate (both 32-bit and 64-bit versions), and Ubuntu Linux 9.10 on my Mac Pro (2.66GHz quad core with 8GB of RAM, running OS X 10.6.2).
Unlike Parallels and Fusion, VirtualBox doesn't have any installation assistants to help you through that process, so I had to install these OSes and create the virtual hard drives for each one myself.
Those chores aren't that hard, but they make VirtualBox harder to use than those other two.
Note also that unlike Parallels and Fusion, VirtualBox won't let you install OS X Server as a guest operating system, nor can you use a Boot Camp Windows installation as a virtual machine.
Once it's installed, VirtualBox 3.1 looks much like the last version. It has windowed, full screen, and integrated (which VirtualBox calls Seamless) views of your guest operating systems. Seamless mode isn't as well integrated as its counterparts in Fusion and Parallels: Separate Windows programs don't become separate application windows in Seamless mode. When you click on any one Windows window, all of them come to the foreground, which makes Seamless mode less useful.
I found the new VirtualBox slightly faster than the last version, but it's still noticeably slower than either Parallels or Fusion. Slower here is a relative term, though. The program is plenty fast for standard office tasks. It took only seconds to launch Office 2007 applications, responded reasonably to scrolling through a graphics-rich Word document, and opened and calculated a complex Excel worksheet rapidly.
In Linux, OpenOffice also ran well enough for typical office use--again, VirtualBox wasn't the quickest, but it was sufficient.
Graphics, gaming, media
In 3D Windows performance, VirtualBox also lags its competition. While there is some basic DirectX support, there's only minimal support for the Aero interface in Windows. I wasn't able to get any of my three test games (Half Life 2, Call of Duty 4, Flight Sim X) to run. You may have more success with older games, but anything relatively new will probably not work in VirtualBox. On the Linux side, basic OpenGL games worked fine.
Unfortunately, just getting that 3D support running in Windows is more difficult than it need be: You must boot Windows in Safe mode, start the Guest Additions install, check off the box for 3D support, finish the install, and then reboot in normal mode. Neither of the other virtualization apps make you go through such gymnastics.
VirtualBox does have good OpenGL support, offering OpenGL 2.0 acceleration to both Windows (32-bit versions only) and Linux. With OpenGL 2.0 acceleration, I was able to run Ubuntu 9.10 with full visual effects (such as windows deforming when dragged). In our Cinebench OpenGL benchmark test, VirtualBox lagged behind Parallels 5 by about 20 seconds.
Overall, video playback is disappointing in VirtualBox. While playback of a 1080p high definition Windows Media file in XP Pro was quite good, that same video completely crashed the virtual machine in 32-bit Windows 7 and played back very slowly in 64-bit Windows 7.
I ran into a few other problems with VirtualBox 3.1--surprising, as my experience with the prior version was relatively trouble-free.
For example, I found I had no sound in the 64-bit version of Windows 7; I had to update the driver. While installing the Office 2010 beta in Windows 7, I switched the virtual machine from full screen to windowed mode, and it crashed. In Ubuntu 9.10, with full screen mode and 3D effects enabled, selecting windows was glitchy. Testing the same operating systems on my MacBook Pro, I ran into similar problems.
As a tinkerer, such crashes are annoying; if you're relying on the product to get your job done, they're much worse than that. Problems like these make VirtualBox feel less finished than its two competitors.
Macworld's buying advice
Overall, VirtualBox 3 works well for typical office tasks in Windows and Linux. Support for multiple CPUs and OpenGL 2.0 in both Windows and Linux are both welcome additions, as are the revamped settings screen and toolbar in full-screen mode. VirtualBox is also the least expensive virtualization app for the Mac.
That said, VirtualBox is definitely the least polished of the three main virtualization solutions. Limited integration between the Mac and guest operating systems, the lack of installation assistance, sub-par 3D support, no support for OS X Server virtual machines, and the occasional crashes mean it's not the best choice for business use.
The program has come a long way since the first Mac release. But it still has a long way to go to catch up with its Parallels and Fusion, both of which offer better features, performance, and stability.