I and my associate have just performed a rendering test of Bryce 4 and Bryce 5 using the scene shown.
All settings were kept identical and both renderings had an output size of 540 x 360 pixels with normal anti-aliasing.
We used a 500 Mhz AMD K6-2 pc under windows 98.
The render times were:
14 minutes 56 seconds in Bryce 4.1,
17 minutes 28 seconds in Bryce 5.01.
conclusion: I have never before seen a newer version of a graphics program actually get slower. I also felt much sadness.
"An Example is worth Ten Thousand Words"