Hi. I too tried to join Vista SP2 x86 and Vista SP2 x64. Each one is installing fine and fast in VirtualBox. But whey they are "together" the setup is very slow, beginning with the window that shows the editions. Specifically each window appears after many minutes + pressing the buttons to do something inside the window is also carried out very slow (for example when you want to format the partition). The setup isn't frozen, you can move the mouse easily. In the host OS Task Manager shows that one of two processors is constantly at 100% (VirtualBox). Soon as the next window appears or the command is carried out the processor usage drops to 0. Can you please help me solve this problem? Thank you in advance.