Meh, who knows.  These days, GPUs are actually far ahead of CPUs in terms of speed, which is why some tests (using top-notch CPUs and GPUs) indicate that SLI actually slows down the computer.  So the extra CPU power present in the PS3 may not have a detrimental effect.

PS3, IMO, is still far stronger than the PC in terms of number crunching.  And price to performance wise, the PS3 is a lot better.  8 PS3s are enough to build a supercomputer...