I follow the blog Microsoft Dynamics CRM UK Blog which is very good and they had an interesting posting today concerning performance issues in virtual PC 2007 on laptops. As most consultants, I use one (a lenovo T61p). You can read more about it here: http://blogs.msdn.com/ukcrm/archive/2009/05/07/virtual-pc-2007-performance-tweaks.aspx
When I tried to apply the change to the file they mentioned (%appdata%\Microsoft\Virtual PC\options.xml) I had a problem since I didn't have the parent tag in my file. I checked around a bit and found that it could just be added to the main structure. So, after modifications, my file looked like this:
I would recommend adding it, if you most of the time have the computer connected to the power outlet, since it will probably increase the performance of your virtual machines!
Microsoft Dynamics CRM Architect