Can you post a link to the MSDN article where you have read this? Because it is not correct.

You can set the MAX MEMORY setting to a much higher value (see MSDN http://msdn.microsoft.com/en-us/library/ms178067(v=sql.105).aspx), depending on the version and the memory available on the machine. Keep in mind to always reseve some memory for the OS when setting the MAX MEMORY for SQL. For example when the machine has 4GB of RAM, only set 2 or 3GB as MAX MEMORY for SQL.