Render times are going to be slow no matter what you do. A video card will speed up your working time as it speeds up redraw. The more RAM you have, and the better the processor the faster the render will be. You can also use tricks, use backdrops instead of building whole backgrounds. Composite, Render your background, then put it on a 2D plane as a backdrop. Try not to use too many volume of glass textures. It's going to be slow to render no matter what you do. That's just the nature of 3D work

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