Athlon 64 processors are so fast exactly due to their high computational power. That is why their indisputable victory in special math1ematical software packages is quite logical.
However, there is another interesting thing here I would like to draw your attention to. First of all, Mathematica is one of the few applications that cares a lot about the size of the L2 cache memory. The advantage of Pentium 4 processors on Prescott 2M core over their predecessors on the regular Prescott core working at the same clock frequency appears about 7%, which is nearly the maximum value we see in this test. Secondly, Mathematica is very loyal to the Pentium 4 Extreme Edition processor working at 3.46GHz and based on the old 130nm Gallatin core. As we see, this CPU turns out a performance leader among Intel CPUs despite its not very high working frequency.
As for the MATLAB test package, the situation there is quite common that is why no additional commentary is necessary I assume.