C++ Direct X vs C# Managed direct X performance

As shown above, I'm wondering does the Native DirectX (written in C++) work better than managed DirectX (written in C# or VB.NET)? There are reasons for this question. But the reason have persuaded me was: For example of a situation rendering H.264 Video(D1 or HD) Streaming, Managed DirectX procedures call to the display driver through .NET Framework, and Native DirectX did not. So what is your comments?