Master of RTFM
As you know from the other thread, that was not a correct assessmentSomething is not clear. The SC-587 the original FM9 uses has 500 MHz DSP cores and a 450 MHz ARM core, the only slightly more powerful chip I can see on analog devices site is the SC-589 which has a 500 MHz ARM core but still the same 500 MHz DSP cores.
Afaik the ARM core is not used for audio processing in the FM3/9 so using that chip shouldn't produce a 10% performance boost. Maybe it's a chip from a different manufacturer?