A few of the ones I've tested...
Particles DON'T render:
Simulation_Fluid_TapWater (same for all the "Fluid" scenes)
Particles DO render:
I've dug through the settings, searched here and in XSIBase, scoured the docs, etc., and can't find a solution.
What's kinda odd is that when I previously loaded the same exact scenes with the XSI 6 Fnd 32-bit trial version that I used for the last month, they rendered OK.