yeah if you can afford a 480 and 460 just get a 1070 or a fury X which is pretty cheap right now (if you have free sync), always get the single better card if you can.
In some strange DX12 multiGPU setup perhaps, but it is not going to work in a normal scenario and it is not worth it. even in DX12 it will not do much. if you already have a 480 then keep it, if you have a 460 sell it and get a 480.
yeah if you can afford a 480 and 460 just get a 1070 or a fury X which is pretty cheap right now (if you have free sync), always get the single better card if you can.