Thank you. A well researched piece of work which explains the comments.
It does surprise me and does not fit with what I believed I knew. So much to learn, I wonder who, if anyone, I can get to review this. Young Mr Hotz would get to the bottom of this in no time but sadly he is no longer interested. I wonder if I can interest anyone else.
I have very limited knowledge and a 20 - 30% increase in memory for 64bit apps makes no sense to me.
My first thoughts are that it is 32 bit apps being poorly recompiled that is causing the problem, in which case Apple would address that rather than just throw more RAM at it but I really do need more information. I will see if I can get it.