Making the Switch: VMWare vs Parallels

A few years back when I first make the switch from Windows XP to OSX 10.4 (at the time) as my default platform of choice I knew there would be a few challenges. Mainly I knew that being a .NET developer there were a number of applications I really needed to run that didn't exist on the OSX side of the equation, specifically the Microsoft Development Stack.

At the time that Apple switched from the PowerPC platform to Intel a competition sprung up to see who could be the first person to get a copy of Windows running on Apple hardware. Eventually a bunch of hackers solved that problem. Shortly thereafter Apple released Boot Camp, it's semi-official (Beta) take on running windows on a Mac. Then Parallels threw their hat in the ring with a virtualization product that in no simple terms kicked ass. Finally a few months later veteran virtualization powerhouse VMWare brought out VMWare Fusion to compete with Parallels.

Today the offerings from VMWare and Parallels are very similar. They both offer Windows 7 support, a coherance / unity mode which breaks windows applications out of the windows desktop and several other bells and whistles you would expect from a fully featured product designed to help switchers.

One of the questions I get asked frequently by people looking to switch is which one do I recommend. The truth is I recommend both but I use VMWare Fusion.

Ultimately there were two reasons, at the time, that I chose Fusion:

1) At the time (and still now I believe) it managed RAM better than Parallels.

Specifically it didn't pre-allocate all of your allotted memory up front. What that means is when you set up a virtual machine you tell it how much system memory it can use. On my 4GB machine i allocate 2G to my VM.With Parallels when you allocated 2 gigs the virtual OS takes all 2 gigs up front and then the virtual OS manages it. Basically its like your running 2 machines and each has 2 gigs of ram.With VMWare if you allocate 2gigs it will give the virtual OS as much memory as it needs at any given point in time UP TO 2gb. After that it begins swapping to disc like any normal OS would. So if your not doing much in your VM OSX could retain 3gigs to use as it sees fit up until your VM needs that extra gig.

This comes in handy when your doing a simple windows task like testing an application in IE or opening word to work on a document. Usually windows wont need all of the memory you give over to it leaving iTunes and all your OSX apps free to eat up that space.

2) I work for a company who uses VMWare in our server infrastructure. We run VMWare ESX servers which means we have a number of VMWare formatted VMs. Fusion is able to open and run many of these VMs which makes life easier if I want to copy over an image of a particular server setup. Really this is the reason I broke out the credit card one day and bought Fusion. But if i were starting from scratch all over again I would go with Fusion from the get go because of number 1.

That's pretty much it, in every other way the two products are competitive and to be honest I'm not even sure if number 1 is relevant anymore (by all means if its not please leave a comment.)

It's worth noting there is a third option, Sun's VirtualBox, which I have not personally tried. I have heard good reviews but I've also head it lags behind the commercial products in feature set so if you can buy one of the commercial ones you should.