Server Editions

Windows Server ships in many software packages, each aimed at a different server role or market. (See the illustration “Windows Server Family” and the chart “Windows Server 2008 R2 Edition Comparison“.) However, large organizations in volume licensing will typically buy three general-purpose OS editions (Standard, Enterprise, and Datacenter), or two specialized editions, Windows Web Server and Windows Server for Itanium-Based Systems. Organizations can also buy Standard, Enterprise, and Datacenter licenses as part of a server license suite. (See the chart “Suites That Include Windows Server Licenses“.)

With Windows Server 2008 R2, all of these editions except the Itanium edition run exclusively on x64 64-bit processors; previous versions of Windows Server supported both 32-bit and 64-bit processors. All editions of Windows Server 2008 R2 (whether bought through volume licensing programs or directly from an OEM with purchase of server hardware) include rights to downgrade to lesser editions; for example, a server licensed for Windows Server 2008 R2 Enterprise may run Standard instead. Downgrades are also permitted to equivalent or lesser editions of earlier versions, including Windows Server 2008, 2003 R2, 2003, and Windows Server 2000.