A: In OSs prior to Windows Server 2008 R2, any user could make use of the full resources of a Remote Desktop Session Host. When resources were available, this relaxed distribution of resources didn't create a problem; however, when resources became scarce, the actions of one user could consume resources that were needed by others.

The Fair Share CPU Scheduling feature in Windows Server 2008 R2 reduces the effect of users who make heavy use of resources by distributing processor time equally across the number of active sessions. With this feature in Server 2008 R2, the actions of one user can't affect the performance of the system for others, even under high load.