Im not sure why you are recommending old GPU's or why you are even going to the AMD side. Your CPU will render things quickly and it will do the job by itself, that being said most programs don't really utilize GPU rendering that well anyway. Many programs need the GPU for live pre-render so you can see what you are editing, not in the final step when you are exporting. That being said although the 600/700 series do have worse CUDA performance than the predecessors its not gone, so if you find a program that will utilize the GPU for rendering you will love your GTX 700 Series set up. Also for gaming it is the best bang for the buck, as well as performance.