No way to allocate RAM that will work, other than killing all unnecessary processes, because the system will just read/write to disk all the time, no matter how much RAM you have. I believe the G5s work better with memory management, but I also believe Poser has not been written properly for OS X. Poser 5 was just as bad. I'm not sure if they have released SR2 yet, but maybe patching it with SR1 will help; maybe not. If your G4 is slow with properly-written software as well, you may have bad RAM.