In February, 2008 MacTech Labs published the quintessential comparison of VMware's Fusion and Parallels Desktop. Since then, Vista SP1 was published and both virtualization products have matured. On Wednesday, MacTech Labs revisited the two programs and asked the Big Question: Which one should the prospective customer choose?

In the initial analysis, the focus was on application benchmark testing. Vista was fairly new, service pack 1 (SP1) wasn't released until March 18, 2008, and XP was still the favored OS for the vast majority of Windows users.

Boot Camp was also assessed.

At that time, the author Neil Ticktin, editor-in-Chief of MacTech Journal, concluded:

"If you don't want Mac integration, and just want to run Windows, go with Boot Camp. It's faster than a PC anyway.

"If you want a virtualization product (that allows you to run Windows alongside Mac OS X) and you want the best performance for the types of things that we tested, then clearly you need to run XP and not Vista. Furthermore, in our tests, both VMware Fusion and Parallels performed well, and were a good user experience. That said, Parallels was somewhat faster in general than VMware Fusion for XP.

"If you want the best virtualization performance for Vista, then VMware Fusion is your choice.

"And, if you want to keep your Mac OS X and Windows environments completely separate, VMware Fusion's design may be your better choice. (And, although we didn't test it, we would expect VMware Fusion to have better multi-processor support if you really have an application that is designed to take advantage of it.) If your goal is tight integration between one or more Windows applications and Mac OS X, Parallels is the clear winner when running either XP or Vista. And, as we said before, if you want the best XP performance with the types of applications tested here, Parallels is not only faster than VMware Fusion, but it's faster than Boot Camp on average for the applications that we tested."

Jump Forward to Present, March, 2009

Armed with the previous experience testing the products, Mr. Ticktin has updated the analysis in "Head-to-Head: Parallels Desktop for Mac vs. VMware Fusion" which will be published in the April 2009 MacTech Journal, print edition. Since the initial testing, Fusion has moved to version 2, Parallels has gone to version 4 and Microsoft has published Vista SP1.

The thorough testing of these products can be a difficult task. Mr Ticktin noted:

"Sounds simple enough, right? But when you start to realize that there were four different models of Macs, two virtualized environments, XP and Vista, some of which were 64-bit and multiprocessor, along with a whole slew of tests, each that had to be runs several times, there were over 2500 tests completed, timed with a stopwatch."

The new report bears careful reading to understand these conditions. On the user side, additional factors need to be taken into account, "speed, footprint, graphics capabilities, features, user interface, OS you want to run, and more all come into play," Mr. Ticktin wrote.

The principle conclusions this time around were:

• The Vista speed "penalty" is mostly gone thanks to SP1 and improvements in the virtualization products themselves
• More RAM doesn't necessarily help. 1 GB of RAM assigned to the VM works best.
• In terms of the test suites that included Windows launch performance, CPU performance, File and Network I/O, Mac Footprint, Application Launch, Application performance and 3D and HD Graphics performance, Parallels was the winner in the first four categories, Fusion in the fifth and a rough tie in the last two.

However, there were some special circumstances to be noted, and the MacTech article itself, of course, provides the definitive results, not this summary.

"One thing is clear, given the track record, expect Parallels Desktop and VMware Fusion to both keep getting better and better," Mr. Ticktin concluded.