Ok so we want to inspect our code and quickly see a list of the top 10 worst performing methods when we do a quick run through of our asp.net web application.
We double click on the worst performing method and <gulp> its something you yourself have written (heavens above).
Next step is to drill into the method with a simple click on the tool and there we go, we can see all child methods and actually the lines of code which are causing the bottlenecks.
Simply put this tool will identify the areas of concern or the areas where we can attempt to optimize our code (old code for example).
I highly recommend this tool if your wondering just why a certain page is taking longer to load than any other or even if you just want to see how fast a certain method takes to execute.
Check out red-gate at http://www.red-gate.com/ - pretty much all of there products come highly recommended.