What about windows server 2012 & hyper-v performance ?

Hyper-V virtual machine performance are the same as analyzing the performance of an operating system installed on Win Server2012.

In windows server2012 hyper-v performance are very useful, cost effective also. you can create virtualize Hard disk on cluster level and also live VM and storage miggration, replication and network vitualization. 

For details click on following link

http://technet.microsoft.com/en-us/library/dn282278.aspx