Check the available memory for SQL Server.

For SQL server to take more than 4GB of RAM AWE should be enabled using'

sp_configure 'show advanced options', 1RECONFIGUREGOsp_configure 'awe enabled', 1RECONFIGUREGO

For AWE to take effect you should restart the SQL Server.

Next configure the memory.

sp_configure 'min server memory', <New Value>

RECONFIGUREGOsp_configure 'max server memory', <New Value>RECONFIGUREGO