AMD has more, smaller, stream processors while Nvidia has less, larger and faster clocked, ones.
So even though AMD might have 3x as many stream processors as Nvidia has CUDA cores they perform about the same.
Neither are really better, just different ways to go about it.
AMD cards don't have a shader clock because it runs at the same speed as the core clock.
Effective memory clock mainly has to do with the bus width, Nvidia uses wider bus' at lower clocks while AMD uses smaller bus' at higher clocks. Bus width x clock = memory throughput