At http://peterkellner.net/2009/05/06/linq-to-sql-slow-performance-compilequery-critical/comment-page-1 there is a very useful article by my fellow MVP Peter Kellner.
This shows that ADO.NET is very much faster than LINQ to SQL unless the latter is compiled. Whilst there may be some cases where Linq to SQL offers genuine benefits, however we should proceed with caution in using Linq unless it a some single use form of query.
I suggest after reading Peter's post you leave a note of appreciation for his investigative work.