What is the difference between Windows Server 2012 R2 Standard edition and Windows Server 2012 R2 Datacenter edition?

Both Standard and Datacenter editions provide the same set of features; the differentiator is the number of Virtual Operating System Environments (VOSE).

• A Standard edition license entitles up to two VOSEs on up to two processors (subject to the VOSE use rights outlined in the Product Terms document for Commercial Licensing or End User License Agreement for other channels).
• A Datacenter edition license entitles an unlimited number of VOSEs on up to two processors.