Yes, the high-poly figures and the 4000x3000 textures eat RAM like crazy.  Poser seems to not release things from memory when it's done with them, either. I was watching the memory usage during a rendering last night. It started out with Poser.exe using about 430 megabytes. By the time it was done rendering an hour and a half later, it had gradually crept up to almost 1.4 gigabytes. That makes no sense. With other rendering programs you can see it dumping things out of memory as the rendering progresses.