SQL Server - Difference between installing a "Default Instance" vs a "Named Instance"

Difference between installing a "Default Instance" vs a "Named Instance"

 

The min difference between a default and named instance is related to network connectivity.  Clients can connect to the default instance using only the host name over the 1433 port.  To connect to a named instance, clients specify the host and instance name (e.g. "MyHost\My_Instance") and the SQL Server Browser service returns the port the named instance is listening on.

 

You can only install one default instance but can install multiple named instances.  It is best to install only a default instance unless you have a need to install multiple SQL Server instances on the same host. e.g. running different versions concurrently or other isolation requirements.  The additional instances must be named.

The benefit of the default instance is that you connect by specifying the server name (eg, MYSERVER), whereas a named instance will require an instance name as well (eg, MYSERVER\SQL2005).

 

If you use a named instance you will need to have SQL Browser running or provide port information in the connection information.