It's like...
Route A - 100m, in 1min it can used to deliver 100 times
Route B - 150m, in 1min it can used to deliver 70 times
Let say the Ghz in CPU is the speed to deliver, both of them uses the same speed but the Architecture (which is the road) is better, Route A which is used to depict a CPU with better Architecture @ the same GHz will perform better.
If Route B would be faster (or higher GHz),
In terms of CPU,
A - 3GHz, better architecture
B - 3.5GHz, lousier architecture
both will perform the same.