johnpenn, I'm running OS9.2 and I'm test rendering with Bryce5.1 and Bryce4.1. So everything is upgraded to the latest version except the OS. Have you done a side by side like the one I did? I have a hard time believing that B4 would be so much faster with the same settings. I got the results I got and I repeated it a few times to be sure. Have you updated to Bryce5.1?