Are there any performance limitations when running a VM of a Boot Camp installation? I'm planning on installing Windows on my Mac, and would like to be able to use both Boot Camp (for when I need to be able to use all of the hardware of the computer) and a virtual machine (for those times when I don't want to restart).

I noticed that both VMWare Fusion and Parallels allow you to set up a virtual machine which uses the Boot Camp installation, which is exactly what I want because I want to have one installation of all the programs.

However, I'm wondering if using a virtual machine with the Boot Camp installation has the same exact performance as creating a brand new virtual machine.

The thing that prompted me to think that they might not have the same performance is the marketing text on VMware Fusion's website:


  Boot Camp Improvements — Up to 5x faster disk performance with Boot Camp virtual machines and a new option to disable authentication.


... which I understood to mean that, in the past, a normal virtual machine (i.e. one that doesn't use Boot Camp) was faster than one that uses a Boot Camp installation, and now with the upgrade, it's 5x faster... yet it's still not as fast as the normal virtual machine (since then they would probably mention that it's now as fast as a traditional virtual machine).

Is there a performance difference when using a normal virtual machine vs. one that uses a Boot Camp installation in VMware Fusion or Parallels? If so, which one is faster and by how much?

Update: Since there are two attributes to compare, the wording is a bit confusing.
For clarification, let:


  A = Performance of normal VM on VMware Fusion 3
  B = Performance of Boot Camp VM on VMware Fusion 3
  C = Performance of normal VM on VMware Fusion 2
  D = Performance of Boot Camp VM on VMware Fusion 2 


I understood the marketing text to mean B = D * 5, and I inferred A &gt; B since they mention that Boot Camp needed improvements, and rather than saying it's now as fast as a normal VM, they give a "5x" figure.
As I use it on regular basis I can say it's good performance of using Bootcamp installed windows via VMWare Fusion 3.

Here is process I followed.


Make a bootcamp partition using Bootcamp Assistant for the space.
Install the Windows XP version.
Open the VMware and select the bootcamp partition, when you create a new virtual machine for Windows.
VMWare installs few utilities on the bootcamp partition, to use it to boot via Fusion.
Once all this is done, you can launch this windows version like a normal virtual machine in Fusion.


If I want a lite usage of windows I will boot via Fusion, if I want to run heavy programs then I will boot into Bootcamp, but I rarely does it, as Fusion VM is 99% OK for me for all activities including development with Eclipse.