Also experiencing this problem, although on a 64bit system (Win8.1 Update 1). Have been in contact with Larian via email, but apart from recommending disabling SLi (which has made no difference) they haven't been able to suggest anything useful.

Have been following development of this game for ages (and played the hell out of the previous entries in the series) and had been rather looking forward to playing it, but at present I'm spending more time looking through these forums and this thread than actually playing the game. Crashing on save seems to be the sort of issue that one would think would be caught during playtesting...