Upgrading to SR4.1 is supposed to increase stability, I've noticed a little difference in the speed of FireFly and perhaps the overall quality of renders if shadows and lighting is used carefully. You shouldn't have any major problems running Poser 5, you may find more RAM necessary in the future - I've got over a GB of RAM and am currenlty thinking of slapping on a further GB to keep Poser sweet for some of the big scenes I try and create. I'm only on an AMD 2400+ but it's suiting my needs until I can raise the capital I need to build my monster :oD Moving over to XP is a good idea, I hope it's Pro and not Home, glad to hear you've having fun though - after all that's the point isn't it?