I've run 2 rather similar codes, one using unmanaged DirectX in C++, and another doing roughly the same thing using managed DirectX in C#. The one in C++ runs quite smoothly, with no hiccups or slowdowns whatsoever, however the one written in managed DirectX was only able to update the screen every second or two.

Since the C# code was written by me, and the C++ code was pulled from the internets, one could attribute the performance difference to my poor coding skills, yet that one would be a n00b. ...

...Or Santa Clause