I have the same issue, well relatively.

Machine:
  Dual core 2.66;  8gig  memory;  64-bit Vista Ultimate; Two 500gig drives with Poser Pro on C: drive and the swap file on E: drive. I've shut down most of the extraneous junk running in the background of Vista. (If you haven't done this, I highly recommend doing it. There are a lot of unnecessary services running by default in Vista.)

Poser Pro has been setup to use 4 threads in separate processes. I've played with the rendering settings as well, but to no avail. I have noticed though that Poser Pro does not seem to manage memory very well, it seems to load up the processor thus bringing the system to it's knees. Sadly, most of my renders and animations are single characters with nothing dynamic. I too experience slowness in moving objects and rendering. If I change cameras, it takes about 5-10 seconds before Poser responds. The 64-bit rendering is nice, when it works, but it too does not manage memory well.

Any ideas? Is there a way to get Poser Pro to better utilize memory?  I'm about ready to go back to Poser 6 or 7. I'm slowly learning Carrara hoping that will work in place of doing some animation in Poser. And for what it's worth, the Collada is not as good as originally promised. But that is for another thread.

Sorry vxg139, I wish I had some good advice instad of being in the same boat. My files are generally 5-60MB, so I doubt it would be a file size issue.

thanks,

-p