Max Memory Size

To the best of my knowledge, Microsoft SQL Server will use all of available memory of the machine on which it is installed, if it need to.

 

To limit SQL Server to use a specific amount of memory, open SQL Server Management Studio, connect to SQL Server, right click on the Server node, click on Properties, then click on 'Memory' tab and change Maximum Server Memory (in MB) value to desired number.

 

Hope it helps!