Here’s a great article you might be interested in:

Presents a low-level cost model for managed code execution time, based upon measured operation times, so that developers may make better informed coding decisions and write faster code. Also highlights the CLR Profiler. (30 printed pages)

URL: http://msdn.microsoft.com/library/en-us/dndotnet/html/fastmanagedcode.asp?frame=true&_r=1

Here’s a great article you might be interested in:

This article provides basic facts about interoperability between managed and unmanaged code, and guidelines and common practices for accessing and wrapping unmanaged API from managed code, and for exposing managed APIs to unmanaged callers.

URL: http://msdn.microsoft.com/library/en-us/dndotnet/html/manunmancode.asp?frame=true&_r=1