The video card won't make any difference at all. Bryce rendering doesn't make use of video card hardware or software acceleration (except for when the work window is set in OpenGL or Direct3D, which isn't the same as rendering a file). Video cards are for rendering to your monitor in real time - the processed information doesn't go back into the computer or back to Bryce - it goes to the monitor (many times per second) and is gone. The last sentence of the first post says that certain attributes were set identically. This may be a clue, because it possibly implies that the scenes were created separately on the two machines / Bryce installations. If this was the same Bryce file, it should be obvious that all the settings were identical and the mention of them would seem redundant. If this is the case - that the scenes were created separately but supposedly identically - then that would explain the difference. For true comparisons of computer performance the same Bryce file should be used on all machines being compared. Any slight variation (changing one setting by just 0.01) will result in some changes to the results in the render report. The differences in the reports in question are quite marked, so it is likely there is a fairly important different setting somewhere, in the Render Options menu, perhaps. If the rendered image was brought across without any intervening post processing, then it should look identical to the other. It doesn't, and all else being equal, that difference in appearance points to a difference in Bryce settings. The most obvious candidate is 'Gamma Correction' under the 'Post Processing' header in Render Options.