I put Poser on a different drive (I don't install any apps to the OS partition) and it works just fine.
Runtimes are on yet another drive, since I frequently have to move the darn thing to a bigger one lol.

Win7 64bit is much (MUCH) faster for me than my old Vista 32 bit Ultimate, and P8 works a treat.
Renders real quick, too, even with IDL on.
Of course, it helps to have oodles of RAM and I run 2 1gb NVidia cards slaved together...

Silke