Update: I have many visitors coming here from search engines. So here is a quick update if you want to use NProf with XNA 4.0. When you run NProf with your game, if the UI of NProf stays empty after running your game, it’s because you are running a XNA 4.0 game. There is a… Continue reading NProf : A Simple, Efficient and Free XNA Profiler (3.1 and 4.0)