Optimizing member variable order in C++

Question

I was reading a blog post by a game coder for Introversion and he is busily trying to squeeze every CPU tick he can out of the code. One trick he mentions off-hand is to

Answer 1

In C#, the order of the member is determined by the compiler unless you put the attribute [LayoutKind.Sequential/Explicit] which forces the compiler to lay out the structure/class the way you tell it to.

As far as I can tell, the compiler seems to minimize packing while aligning the data types on their natural order (i.e. 4 bytes int start on 4 byte addresses).