virtualbox.org

I have verified on several PCs running Windows 7 Professional (RTM) that the Windows 7 XP Virtual Machine and the Sun Virtual Box can live together BUT DO NOT play well together. Do not even attempt to run both at the same time. The XP VM dies and becomes corrupted. The Virtual Box hangs. Either works OK as long as the other is not running. I had to uninstall Windows 7 VPC and XP VM and reinstall from scratch after the XP VM became corrupted while trying to run with Virtual Box running. I have XP running in a Sun Virtual Box on one PC and now have Windows 7 XP VM running on another (almost identical AMD Quad systems). Both VMs have the same software installed. It will be interesting to see if there is any significant performance difference. The XP VM does now support USB drives. The only advantage I can see for someone with Windows 7 Professional to run the XP VM is that they get a legal copy of XP. I already had several legal copies of XP so I will probably continue to run XP in a Virtual Box. My first non-scientific opinion is that the XP VM did not seem as "snappy" as XP in a Virtual Box even with the XP VM running on a slightly faster AMD Quad system. I suspect the XP VM video driver is not up to the level of the Virtual Box video driver.

Taken from the VirtualBox Users Manual. Section 1.2

Warning
Do not run other hypervisors (open-source or commercial virtualization products) together with VirtualBox! While several hypervisors can normally be installed in parallel, do not attempt to run several virtual machines from competing hypervisors at the same time. VirtualBox cannot track what another hypervisor is currently attempting to do on the same host, and especially if several products attempt to use hardware virtualization features such as VT-x, this can crash the entire host.

My playing around with XP VM and VB is proof positive that IT WILL NOT FLY! I should have looked in the VB manual now that I think about it. Oh well, it was interesting to prove what the manual stated would happen. I was on a test system so I was not really concerned about crashing the machine but DO NOT TRY IT ON A PRODUCTION SYSTEM.