"Warning: Intel's C++ compiler cannot compile the QD library with anything above -O0 correctly, that puts all Intel based machines at a severe disadvantage compare to PPCs or Power systems. g++ does compile the QD code correctly, however it currently produces not quite so fast executables and it seems to be impossible to link g++ code with Intel ifort (version 8) code, that is a massive performance problem for all IA-32's, IA-64s and AMD64s. "
From the Benchmark background. I don't think this was exactly a fair test, once again. He also notes its a test of the compiler... and, to be blunt, IBM rules all in this area (xlf95 is amazing). The performance of the G5 is not surprising.... although, I think with a different piece of code (without having to do the link from fortran to c that the intel cannot handle, apparently), the results might be "closer". I'm shocked with the Itanium results.
Example: the code I'm writing for my dissertation runs 400% faster with ifc8 than with g77. Same computer, same operating system, just different compiler.