It is a year since I am using Virtual PC, but I think I should finally start reading the Help, because I missed so many nice features like: differencing disks, virtual hard disk compression.
With differential hard disks You can create a base image, like Windows 2003 OS and create additional images that will contain only the changes. It seems that it is possible to chain the diff disks or in other words it is possible to create base OS image, then install SQL Server on a diff machine, then on top of that - Visual Studio if You like.
I have tryed to use diff disks on my notebook. Well what I can say:
- The diff disks are just a bit smaller than the full version
- If HDD is slower (like notebooks usually have) reading from two files impacts performance a bit
- Read only diff disks (like Domain controllers, which are used for storing accounts) can be compressed using NTFS compression features. In my case 1.5 GB diff disk was compressed into 60MB file on disk, which is amazing then.