Note 39 (page 98): Notice that the use of the const parameter, which is generally relevant only for strings, can speed up inlined code, as it can help the compiler produce better code. Consider it as an optimization suggestion for the compiler in the case of inlining. The Max function shown earlier uses it, like most of the RTL inlineable functions.

This blog post is part of my "113 Delphi 2007 Handbook Notes" blogging project, to promote my new Delphi book.