Microsoft has made great strides with the release of Hyper-V 3.0, particularly in the area of scalability. Although most organizations will never reach anywhere close to maximum possible configurations, the table below shows you the maximums for a number of elements. You're shown Hyper-V 2008 R2 maximums compared against Hyper-V 2012 maximums which are also compared against vSphere 5.1 hypervisor (free) and the Enterprise Plus Edition.
|Product version||2008 R2||2012||Free||Ent Plus|
|Physical Memory||1 TB||4 TB||32 GB||2 TB|
|Virtual CPUs per Host||512||2,048||2,048||2,048|
|Virtual CPUs per VM||4||64||8||64|
|Memory per VM||64 GB||1 TB||32 GB||1 TB|
|Active VMs per Host||384||1,024||512||512|