Is Virtual Machine Additions required with Hyper-V?
—In Virtual Server 2005, Virtual Machine Additions moved part of the VM processor into the host kernel. Hyper-V’s use of hardware-assisted virtualization makes that unnecessary. After the guest VM has been installed, you can optionally install integration components that add functions such as a data exchange service. For Windows Server 2003, integration components are necessary to get device drivers for Hyper-V’s synthetic devices.