The latests versions of Poser are supposed? to handle memory more efficiently (plug the holes) than previous versions. So the issue isn't/mightn't be just a 32/64 vs issue, or a Daz/Poser issue, but more a result of more/less memory efficient codes between versions. Or even perhaps achieving a sweet-spot with hardware components (graphics card/memory modules) that cooperate more efficently together.

I must be blessed when I say that Poser (4 thru to 2012) has generally been pretty rock solid for me if I use it sensibly and accept each versions limitations. If you want to hammer nails with a screwdriver, you have to expect problems.