Bryce has used Idle-time processing since Bryce 4. That actually made Bryce 4 slightly slower than Bryce 3 depending on what you were doing while rendering, but also made it smoother and it multitasks better. And Bryce 4 got more idle time in Win98 original than in later Win98's. Windows does more on its own with nothing running in SE and ME. Under the original Win98 Bryce 4 was getting 97-98% of the processor time, but after applying Windows updates to the equivalent of SE, it rarely got more than 92%. Bummed me out. Why all this concern with Bryce 4 projects in Bryce 5? I think Bryce 5 projects render no slower than Bryce 4 if the project is completely Bryce 5. At least that was my experience when I duplicated projects from scratch. Bryce 4 projects do render slightly slower in B5 and I'm not sure why. Spit