> GPGPU can provide about 100 times more speed than CPUs

Ok. You're talking about performance.

> their performance per watt has oscillated during most of the time around 3 times and sometimes up to 4 times greater in comparison with CPUs

Now you're talking about perf/W.

> This is impressive, but very far from the "100" factor originally claimed by NVIDIA.

That's because you're comparing apples to apples per apple cart.