Original post from Dell TechCenter global.
Microsoft has added a number of new features and capabilities to Windows Server 2012R2, as well as updated many as well.
Dell PowerEdge servers, such as the Dell PowerEdge R620 and R720, support Windows Hyper-V, and Dell also offers the Hyper-V role installed (if selected during purchase) when a server has a factory-installed OS (http://en.community.dell.com/techcenter/b/techcenter/archive/2013/11/21/the-top-5-reasons-to-buy-a-dell-factory-installed-oem-operating-system-when-you-purchase-a-new-dell-server.aspx ).
Dell PowerEdge servers can take full advantage of these new capabilities. Storage QOS was developed to prevent any single VM or set of VMs from taking over all the storage bandwidth used by the VHDs in a server.
Read the complete blog here.