In 2005, Intel, and later AMD, built extensions to their x86 chip architectures that took much of the resource-management load off the hypervisors, making it much easier to build a hypervisor that could run guest operating systems as virtual servers without having to modify them first.

Server operating systems are designed to own the chips, memory and other resources in the machine on which they run. Without extra functions built into the processor, chipset and BIOS the hypervisor must take responsibility for marshalling, queuing and executing commands from all the guest operating systems without causing them to conflict, fail or destabilize the base operating system. Virtualization-enhancing additions from the chipmakers (IVT in Intel's case) build the caching and queuing into the hardware itself and provide hooks that both the hypervisor and guest OSes can use to route jobs directly to the processor without destabilizing themselves or other OSes on the machine. VMware introduced a hypervisor for x86-based systems in 1999, but the difficulty in resource-management restricted its performance and slowed the progress of potential competitors until IVT became available in 2005.

• Intel Virtualization Technology (IVT)