Version 3.0 of Sun's xVM VirtualBox software was released on June 30. With just a couple of new features and a slew of tweaks and bug fixes, the no-cost virtualization product isn't an evolution, but one that continues in the right direction.
Here I've assigned two virtual CPUs to a guest Ubuntu system. I conducted this test on a Lenovo T400s equipped with an Intel Core 2 Duo processor so I only assigned two CPUs. The VirtualBox documentation suggests that the maximum number of virtual CPUs should not exceed the number of physical cores available.
To enable virtual machine access to the new SMP feature, it is necessary to enable I/O APIC, which avoids IRQ sharing, with the trade-off that it could negatively impact CPU performance.
It's a simple check box parameter to enable the DirectX and OpenGL interface functions during the creation of a virtual machine.
The final result on my laptop is seen here-a Ubuntu 9.0 "Jaunty Jackalope" guest running on top of Windows Vista.