P-code, or pseudo code, is an intermediate step between the high-level instructions in your Basic program and the low-level native code your computer's processor executes. At run time, Visual Basic translates each p-code statement to native code. By compiling directly to native code format, you eliminate the intermediate p-code step.

see:
hxxp://msdn.microsoft.com/library/default.asp?url=/library/en-us/vbcon98/html/vbconcompilingyourprojecttonativecode.asp