When I had XP 32 bit I already had 6 GB of RAM physically installed, but in My Computer>Properties it showed only 3.25 GB.
I'm not sure what the dealio is with that. I remember reading somewhere about Windows "setting aside" a certain amount of RAM for specific purposes depending on (IIRC) what kind of hardware one had installed, so I always figured the other .75 gigs that it should have recognized was being recognized but devoted to something in particular and thus not available for anything else.
