[asp.net] SQL providerName in web.config

We are using ASP.NET (Framework 2) and setting database connection strings (SQL2005) in web.config.

We are currently using "providerName=SqlServer".

All our data accesses are done using System.Data.SqlClient - should we therefore change to providerName=System.Data.SqlClient? I find many examples of this providerName on the web, but very little explaining what providerName=SqlServer actually means.

Is there a difference? I'm worried that the providerName we currently specify is actually referencing a legacy (and maybe slower) client, or is there an even more efficient client than SqlClient for use with ASP.NET?

 WebConfigurationManager.ConnectionStrings["YourConnectionString"].ProviderName;