The NVidia web site allows to find out the 'bandwidths', i.e the amount of data that can get inside the GPU for a same given time, per model.
Of course you quickly find out that the bandwidth raises a lots with the price.
I'm not expert in overclocking. I guess it's something you can try once you know how to watercool your GPU.
For me, not excessive price and absolute silence is my favorite.
Noise can change a lot for the same basic model, depending which manufacturer delivers it. Gigabyte made some Zero Noise absolutely wonderful. Actually, I'm not looking for max power at the moment.