If you have encountered an ISO with the "Ultimate" name, it is likely a modified or unofficially renamed version of , which is the actual top-tier, feature-complete edition. Review of the Top-Tier Edition (Datacenter)
Since "Ultimate" implies the most capable version, this review focuses on the , which provides the full suite of Windows Server 2012 capabilities. Go to product viewer dialog for this item. Microsoft Windows Server 2012 R2 Essentials
There is no official "Ultimate" edition of . While "Ultimate" was a popular consumer edition for Windows 7, Microsoft streamlined the 2012 server lineup into four primary editions: Foundation , Essentials , Standard , and Datacenter .