Virtualization showdown: VMware Workstation vs. Sun xVM VirtualBox

VMware's desktop champion takes the flag, but Sun's free and open source alternative is coming on strong

A two-horse race: That's how the market for general purpose desktop virtualization packages is shaping up, at least for the foreseeable future. With Microsoft all but abandoning Virtual PC (no updates in more than a year), and with everyone else focusing on the datacenter (including Microsoft), the field now consists of just VMware Workstation and Sun Microsystems' xVM VirtualBox. And in keeping with many such situations -- where a single product dominates the high end and everyone else tries to find a viable niche -- the two players couldn't be more dissimilar.

In Lane One you have VMware Workstation, the pedigreed blue blood of desktop virtualization solutions. If there is a bell or whistle VMware missed, I can't spot it. It truly is the pinnacle of "kitchen sink" engineering. In Lane Two you find Sun xVM VirtualBox, a product Sun acquired from tiny Innotek earlier this year. VirtualBox's primary claim to fame is that it's free (both as a closed source downloadable and a more limited open source exploitable), and this has made it the choice of anti-establishment types who balk at Workstation's retail price tag.

So the stadium is set. The track is prepared. It's the muscular thoroughbred vs. the scrappy Ol' Paint. And with Sun pouring its vast engineering resources into VirtualBox (for example, it just gained 64-bit guest OS support), the real race may be to see whether VMware can continue to differentiate Workstation at the high end while VirtualBox slowly eats its lunch among less discriminating customers. It should be an interesting race. And they're off!

Legendary thoroughbred

What is there left to say about VMware Workstation? Few products have spent as much time at the top of the heap. But as I mentioned in my preview of the Workstation 6.5 Beta earlier this year, the company simply refuses to sit on its laurels. With each new major release, VMware raises the bar for would-be competitors. And not just by a few inches -- in the case of version 6.5, think several feet. The change log is that impressive.

But where to begin? I suppose I could talk about my favorite new feature, Easy Install. Simply create a new VM, point it to the installation media for the desired Windows OS edition (client or server), and grab a cup of coffee. By the time you return, VMware has installed the OS (including specifying product keys and default user accounts), slipstreamed its own VMware Tools suite, and basically left you with a fully baked guest OS image that's ready for work. If you spend a lot of time building and tearing down VMs like I do, you will instantly fall in love with Easy Install.

Direct3D acceleration is another great feature. When enabled, it allows applications in the guest OS to render Direct3D objects with nearly native performance, allowing even demanding programs like DirectX-based games to run within a VM. I've personally used this feature to resurrect some of my old favorites -- games such as Starfleet Command 3 -- that refuse to run natively on Windows Vista. And, of course, any line-of-business applications that use Direct3D will also reap benefits.

Of course, the biggest changes involve Workstation's support for VMware's ACE technology. Whereas in the past you had to run a separate version of Workstation -- the ACE Edition -- to edit and apply ACE policies, version 6.5 incorporates these features seamlessly into the base Workstation UI. You can now enable/disable ACE functionality for a VM with a single click, and given the depth and breadth of options available, one click may be all you need to securely lock down and manage a wayward VM. In fact, it seems clear that VMware intends for Workstation 6.5 to be your primary entry point into its ACE management environment, with similar one-click tools for creating ACE packages, including the popular Pocket ACE for USB sticks. Together, the Easy Install wizard and ACE integration features truly take the drudgery out of VM creation, configuration, and management.

I tested VMware Workstation 6.5 under Windows Vista (64-bit) on a 4GB Dell XPS M1710. Installation was a breeze, as with previous editions, and the new Easy Install option made provisioning and configuring new VMs nearly effortless. During preliminary benchmark testing using a Release Candidate build (and with the pre-release debugging features disabled), I achieved OfficeBench throughput levels slightly better (11 percent) than version 6.0 but nowhere near native machine performance. It's worth noting that Workstation 6.5 now allows you to manually override the underlying virtualization model, making it possible to force it to use one of three different modes (Binary Translation, Intel VT-x/AMD-V, Intel VT-x with EPT/AMD-V with RVI) or an Automatic option that selects the best mode based on your underlying hardware and OS configuration. I used the Automatic option during benchmarking.

Overall, VMware Workstation 6.5 is a worthwhile upgrade, especially for customers seeking to leverage VMware's ACE management features. But even without ACE, Workstation 6.5 is compelling. Most users will be sold on Easy Install alone; it's a feature that will make support professionals and developers instantly more productive. And although it's hard to put all of version 6.5's improvements into words, suffice to say that the old thoroughbred has never looked better.

The dark horse

Proud. Scrappy. Spoiling for a fight. These are some of the descriptors that come to mind as I look back over the history of VirtualBox. When I first reviewed version 1.3 nearly two years ago, I found a promising product from a small-time player (Innotek) that was still a bit rough around the edges. Four major releases later, and VirtualBox has undergone some major architectural changes. These include support for 64-bit hosts (including Mac OS X) and 64-bit guests, as well as a more modular/programmable architecture. VirtualBox has also picked up some new tricks, including USB device support. And it has of course found a new home via Innotek's acquisition by Sun Microsystems.

In short, VirtualBox has generally matured into a stable, viable alternative to VMware Workstation, at least for casual usage scenarios. And, of course, it's free -- both to download and to reuse as open source software. In fact, Sun has gone out of its way to promote VirtualBox as the ultimate generic virtualization solution, an everyman's VM tool for bridging the gaps among Unix, Linux, and Windows.

So far, the strategy is paying off. VirtualBox is now everywhere, but it's particularly strong in the Linux community where it provides a relatively full-featured alternative to the free VMware Server or commercial VMware Workstation offerings. And with features like real snapshot support, broad host and guest OS compatibility, and the aforementioned support for 64-bit guests, it's easy to see why. Thanks to a growing user base, VirtualBox is quickly cementing its position as the lowest common denominator for the budget-minded VM enthusiast. Just check out how many VirtualBox disk images are floating around the BitTorrent sites.

Of course, popularity doesn't always equate with quality. Despite major gains in stability and robustness (thanks, no doubt, to an infusion of engineering know-how from Sun), VirtualBox is still nowhere near capable enough to challenge VMware Workstation on its home turf -- namely, enterprise support and development teams managing large-scale projects that actually matter. For these users, features like integration with the Visual Studio and Eclipse IDEs, Easy Install, full VM recorder/playback functionality, and support for deployment and manageability controls (VMware ACE) are basic requirements. Needless to say, you'll find none of these advanced tools in the down-market, “freebie” lane occupied by VirtualBox.

Basically, VirtualBox 2.0 is where VMware Workstation was three to five years ago: a maturing, relatively stable tool for running multiple guest operating systems on a host PC. Still, for many casual users this is all they really need. To them, VirtualBox fills a void between the full-featured Workstation and VMware's free Player application, the latter of which places Workstation's powerful runtime engine in a frustratingly restrictive straightjacket with minimal configurability. So while VirtualBox may not be able to compete with VMware on features (it doesn't have all that many to speak of) or performance (it's at least 30 percent slower in OfficeBench tests on the aforementioned Dell XPS M1710), Sun has managed to carve out a niche where its newly acquired product can thrive while growing stronger and occasionally nipping at the heels of its more capable competitor.

Calling VMware Workstation 6.5 versus Sun xVM VirtualBox 2.0 a two-horse “race” might have been misleading. With Workstation's expansive feature set and top-notch performance, it really isn't much of a competition. Still, VirtualBox delivers a combination of features that you simply cannot find outside of VMware, including USB device integration and 64-bit guest OS support. Add to this the killer price (free) and you have the makings of a cult classic. And though VirtualBox doesn't measure up to VMware Workstation today, don't count Sun out. As one of the preeminent engineering powerhouses, the company has the talent and resources to make a serious run at anyone it targets. VMware had better not let its guard down anytime soon.

InfoWorld Scorecard
Setup (20.0%)
Compatibility (25.0%)
Performance (20.0%)
Value (10.0%)
Ease of use (25.0%)
Overall Score (100%)
VMware Workstation 6.5 9.0 9.0 9.0 8.0 9.0 8.9
Sun xVM VirtualBox 2.0 7.0 8.0 7.0 9.0 7.0 7.5

Copyright © 2008 IDG Communications, Inc.