The NVidia cards are always quite safe. ATI has pretty poor support of OpenGL. I have an NVidia FX5950 and I can load in a million polygons worth of models at once and still move around with barely any performance hit. I have textures on almost all those models as well. One reason you may notice slowdowns is if you have a bunch of textures that are 2048x2048 or bigger loading in. Unless you have a lot of RAM on your video card and on your system, you will get to a point where you can't hold anymore textures and your system will suddenly seize up. At that point, it is shifting to virtual memory which is incredibly slow. I actually don't know how a mac handles it when you run out of system and video memory, my experiences are mainly with a PC. Basically, using lower resolution textures will give you a major performance jump. You can use a free program that can run through a folder of images and batch resample or you could do it by hand. I don't think there is a way in DAZ|Studio for you to set the maximum size yourself right now.