By Rob Horwitz [bio]
Posted: Sep. 15, 2008

The following is a chart accompanying an article published by Directions on Microsoft, an independent research firm focused exclusively on Microsoft strategy & technology. More samples of our content, as well as a list of upcoming articles and reports are also available.

Windows Server 2008 comes in several major editions derived from the same code base. The most important differences among editions are virtualization rules, the number of processors supported, amount of physical memory exploited, and high-availability features. Windows Server Standard also limits two features, Terminal Services Gateway and Routing and Remote Access, to 250 concurrent connections.

Microsoft considers multicore and hyperthreaded processors to be a single processor, regardless of the number of cores and/or threads that they contain. All editions listed include rights to downgrade to lesser editions of Windows Server 2008 as well as equivalent or lesser editions of Windows Server 2003 R2, Windows Server 2003, and Windows Server 2000.

An edition that is specifically targeted at database servers with Itanium processors—Windows Server 2008 for Itanium-Based Systems (IA-64)—is not listed in the chart, but the amount of RAM and CPUs supported as well as high-availability features and price are almost identical to the Datacenter Edition listed in the far-right column. Windows HPC Server (previously called Compute Cluster Edition), used for high-performance computing applications such as mathematical modeling and seismic analysis, is not used with conventional business software and is also not listed.

Prices quoted are the highest price a business customer would pay through a volume purchasing program (i.e., the Open Business program price).