Yes Kunisch, it is quite possible. What you just described is what a \"rolling load\" is. It\'s very common. Anytime you play a game that has \"no\" load times, this is part of what they\'re doing. (decent console games for example)
As I posted before, though, PS currently has allot of VM leaks. Every time you load a new area, it is supposed to unload the last one. It doesn\'t do this perfectly, and eventually the leftovers build up and slow things down. Depending on your system, you\'ll get a popup error and/or slow down to a halt. This is what the devs are working on first. If they didn\'t, the extra loads would reek havoc. (Once all the leaks are fixed, I\'m sure this is on the list of things to peruse.)
BTW, the \"load all maps\" thing gives me a blue screen of death... (It seems you need more RAM than I have...)