svdl,

     Thanks for what you ran. I understand the reason for wanting to run some standardized benchmark, but I had already covered the point that the pre-rendering overhead, which uses one core, would skew results on short renders. :) If one where to look at your numbers alone, the conclusion would be that four cores is not worth while. However, with most renders being of higher quality, the pre-render overhead becomes insignificant and the benefit of additional cores really kicks in. We don't get to see that with these numbers.

     This still leaves my questions unanswered.

     Assuming the render is complex and large enough to overcome the pre-render overhead, I've seen that with my AMD X2 dual core, the second core has provided a performance boost of 85%. If the scene where balanced such that both cores ran for the entire render (with the image split up into halves or quarters based on the number of threads, some threads end before others) the benefit may be even higher.

     True AMD quad core is still a few months away I believe, and I can not extrapolate X2 performance to AMDs current X2+X2, two socket "quad core" systems. Theoretically, Intel's Quad Core should offer a nearly linear benefit for each additional core, once overhead and thread distribution are factored in, for large, more complex renders. Unfortunately, the benchmark tests are not sufficient to show how the Intel quad Core scales in pure rendering performance.

     [Also, (on a side note) maybe someone else might want to test this out for themselves, but I found the seperate process renderer to be undesirable for more than the fact that it produces a performance hit, rather than a performance benefit. When layering renders of the same test scene at the same settings, one from the regular FF render and one from the seperate process FF renderer, I could clearly see that the results were not consistant. There was severe color banding in the background from the seperate process render not present in the standard FF render.]