LINQ query versus compiled LINQ query

Rico Mariani changed his position a few months ago but he still manages to provide his Performance Quizzes from time to time. Today he explains the difference between LINQ queries and compiled LINQ queries. It's obvious that one should cache as much as possible because in most cases is better to pay a high price once then a slightly reduced one many times. But the interesting part of the post is the way how Microsoft came up with their current implementation of compiled LINQ queries. Nearly every good performance solution is a matter of realizing that being very generic doesn't pay off. Crazy about performance topics? Go and solve Rico latest quiz. Once you are done check if you are right.