no, a faster clock speed does not always mean better performance.
it means that it is faster than a CPU with the SAME architecture, but 2 different CPU's don't have the same architecture.
a CPU has a set of pipelines, or a series of transistors that the data goes through and comes out the other side as the answer, changed by the transistors.
AMD makes their CPU's with shorter pipelines, so it doesn't take as long for data to go through. that means even if the data is going through slower it can still get to the other end first.
Intel did not design their Pentium 4's well, their Pentium 3's are more efficient than Pentium 4's. they were even outperforming Pentium 4's of the same frequency when the Pentium 4's had DDR RAM did you know that the Pentium M's are actually modified Pentium 3's? they are a lot more efficient than Pentium 4's.
when Intel made their Pentium 4, they were a bit lazy and decided to just make a CPU that can get high clock speeds. the architecture is called "netburst" and was a bad idea from the start.
AMD has actually improved their architecture, and made advancements like shorter pipelines, an onboard memory controller for much faster memory access, and the ability to process data in 64-bit chunks.