SOLVED: What is the Difference Between Windows Server 2012 Standard and Data Center Editions

In a word, VM’s.  The only difference (other than price) is the number of VM’s you can use.  Data Center provides unlimited and Standard provides 2.

Below is Microsofts conciese explaination of the differences in the versions which I copied from: microsoft.com/licensing/about-licensing/windowsserver2012.aspx#tab=2

Datacenter

Datacenter edition is ideal for customers that want to have a highly virtualized private and hybrid cloud environment. As always, it provides access to all of the product features and enables unlimited instances of Windows Server with each license. The licensing for Datacenter edition will continue to be processor plus CAL; however, with the release of Windows Server 2012, the license will now cover up to two physical processors on a single server.

Standard

Standard edition is ideal for those customers that want to have a physical or lightly virtualized environment. This edition will now enable a customer to run up to two virtual instances of Windows Server with each license and provide all of the same features as Datacenter edition. The licensing for Standard edition will change with the release of Windows Server 2012 and will now be the same as Datacenter edition. The licensing for Standard edition will be processor plus CAL, where each license will cover up to two physical processors on a single server.

Essentials

Essentials edition is ideal for small businesses that have up to 25 users and want to have a simpler, pre-configured connection to cloud-based services. While this edition does not enable the running of any virtualized instances, it can be used in a virtual instance. The licensing for Essentials has not changed; it continues to be a server license for a two processor server that does not require CALs.

Foundation

Foundation edition is ideal for small businesses that have up to 15 users and want a general purpose server. The licensing for Foundation has not changed; it continues to be a server license for a one processor server that does not require CALs and is only sold through OEM (Original Equipment Manufacturer).