Type 1 virtualization platforms that run on the bare metal of your server hardware will have specific hardware requirements because they are not typical applications that run inside an underlying (host) operating system.
Because of this, type-1 virtualization platforms will have strict hardware requirements. For example, Hyper-V must run on 64 bit hardware and VMware ESX Server only support certain disk storage systems and network interface cards.
For more information on the hardware requirements of these two virtualization platforms, please see: