How to: Set a Fixed Amount of Memory (SQL Server Management Studio)
Use the two server memory options, min server memory and max server memory, to reconfigure the amount of memory (in megabytes) in the buffer pool used by an instance of Microsoft SQL Server. By default, SQL Server can change its memory requirements dynamically based on available system resources.
In Object Explorer, right-click a server and select Properties.
Click the Memory node.
Under Server Memory Options, select Dynamic memory configuration.
Enter the desired amount for Minimum server memory and Maximum server memory.
If you use the default settings (by leaving the Dynamic memory configuration option selected), SQL Server can change its memory requirements dynamically based on available system resources. The default setting for min server memory is 0, and the default setting for max server memory is 2147483647 megabytes (MB). The minimum amount of memory you can specify for max server memory is 16 MB.