So

LINQ is a front end too CAML so of course CAML is faster and CAML is a front end too SQL so of course SQL is faster.

However what would be a good test to see where and when to use each of these on a sharepoint site.

I was thinking of processing several huge lists with each on 5 seperate pages and using a performance monitor.

But this doesn't seem like the best option, any ideas? Or does someone know what the real overheads are: 

This is what I have found so far (Oh and my boss insists LINQ is faster than CAML I have to prove him wrong!)

http://blog.metrostarsystems.com/2011/10/25/linq-to-sharepoint-vs-caml-vs-sql-performance/