Hi MarkBunney,
I actually just came across the post you referenced about IO2 and IO3 being able to be run at faster speeds, and was navigating back to this thread so that I could bring up that point, as well as to ask whether that specifically applied to the case when these pins are outputs. You kind of preemptively answered that question for me though.
I am not quite sure that I will be able to use the Galileo for my purposes, as I am trying to execute some successive FFT's and obtain real-time (or close to real-time) data analysis with the signals that I need to sample.