AgileFx is a LINQ-based ORM for the .Net Framework, with features comparable to Entity Framework and special attention given to performance.
AgileFx was started in late 2009 by AgileHead, when customers requested an ORM which is as fast as Linq to Sql, but having the more advanced features found in Entity Framework.
AgileFx extends the Linq to Sql provider with many of these missing features, while retaining its outstanding performance profile.
Linq to Sql was great for performance; it usually produced highly optimized queries comparable to handwritten queries.
Unfortunately, Linq to Sql lacked many important features (like Inheritance and Many-to-Many relationships) which made modeling real world applications impossible.