I agree, jval, it would be a big assumption, which is why I'm not making it ("if"). Glad you're taking the time to read my posts; I wish everyone would. ;-) What I see is a difference in the reported render speeds for Bryce4 scenes rendered in Bryce5, between Mac and PC. There doesn't seem to be an obvious explanation for the difference, so yes, I'm speculating. Bryce is supposed to be written in a code (called something like 'Axiom') whereby the two platforms it is written for get virtually identical versions of the program. If these various benchmark reports are accurate, then clearly that system has not worked for Bryce5. Whether it's the two versions treating default settings differently (somehow hidden from the render report), or whether there is something beneficial in the code for the Mac (or some other reason); the reports so far show that there IS a difference. I've already spoken out in favour of Bryce5 in other respects, and I want to buy the program. But I'm not going to buy until I have a satisfactory explanation for this difference between the platforms. I shall ask on the Corel discussion group (though someone already has and no answer was forthcoming) and hopefully get something meaningful. In the meantime, nothing would be more helpful than render speed comparisons, especially from Mac users (not enough reports so far for reliable conclusions).