My partner and I have been working on creating a realistic looking alleyway. We've gotten up to about 200,000 verticies and we have uv mapped just about everything in the scene. Because we wanted a sunset/twilight effect on the town we used an hdri for the lighting. So here is the problem. When we try to render using Mental Ray, it either takes hours upon hours(for a mere 640x480) or Mental Ray says it ran out of memory and says to please save and shut down.
My computer is an HP Pavilion dv9700 Entertainment PC. It has 3GB of ram, and over half of my 221GB harddrive free. When I'm running Maya I also have a USB plugged in using 4GB of readyboost. I've also tried defragging, and other methods of speeding up a computer. Is there anything I can do to make the render faster/not fail?