Be sure to check out this topic at DAZ: Bryce 5.5 - Information Regarding the Render Optimizations as it outlines in more detail the varying render times that you will experience. Hope this helps explain what you're experiencing. The initial review sounded pretty good, with comments like: "In terms of faster renders, I have to say that there is a noticeable difference. There also seems to have been another AA pass added, because in some scenes some artifacts appear where different materials meet, only to dissapear in the next pass. Definitely faster, nicer, I have to test out some serious computer-deathkneeling scenes to be sure, but some quick and dirties have proven some 20-30% less waiting. GOOD! The only down-side is that even in rendering a sphere over a water plane, every newbie's wet dream come true, towards the last AA'ing pass, my comp pretty much froze." and: "In essence, DAZ delivered on what it promised. It didn't set too high a goal and it certainly brought home the bacon. Now it only has to think harder in terms of Bryce 6. " Of course, it's true, as outlined in the post at DAZ linked above, the render optimizations have come at a price, and the further and further that development progressed, the more and more apparent such concesssions became. Too bad that because some scenes aren't showing a 50% speed improvement, the rest of the review is being trashed. And yes, it's true, the improvements made in 5.5 are small compared to what will be in version 6.0. DAZ learned a lot while working on this point release, and that will be a big advantage when development on version 6 begins. Steve