Microsoft Evalcenter "
Hyper-V Server 2012 R2" - “Evaluation Unlimited”, “Hyper-V Server is a dedicated stand-alone product that contains the hypervisor, Windows Server driver model, virtualization capabilities, and supporting components such as failover clustering, but does not contain the robust set of features and roles as the Windows Server operating system. As a result, Hyper-V Server produces a small footprint and requires minimal overhead. Organizations consolidating servers where no new Windows Server licenses are required or where the servers being consolidated are running an alternative
OS may want to consider Hyper-V Server”.