Here you go: http://www.nvidia.com/object/product-quadro-4000-us.html http://www.geforce.com/hardware/desktop-gpus/geforce-gtx-470/specifications
The last one is what i currently have. as you can see, the quadro's memory bandwith, cuda cores and memory interface are below the gtx. But you have bigger vram which means you can cram more into the scenes. Speed wise, given the differences it might be slower at the actual rendering, but we're talking gpu rendering here so i'm not sure if it's going to be that much noticeable. Do a render with both scenes and post your times in the forum. Then we'll know better how hardware affects the performance. To be honest, i always found quadros to be extremely overpriced, but maybe that's just me.
