How to: Configure the Affinity Mask (SQL Server Management Studio)
To carry out multitasking, Microsoft Windows 2000 and Windows Server 2003 sometimes move process threads among different processors. To enable one or more processors, use the affinity mask option.
In Object Explorer, right-click a server and select Properties.
Click the Processors node.
Under Enable Processors, clear the selection of Automatically set processor affinity mask for all processors.
In the Processor grid, enable one or more processors to configure the CPU affinity for the Microsoft SQL Server instance.