I am very suspicious about the analysis on the FM site. The DR at high iso with efficient modern sensors, which are of very similar efficiency, is limited mainly by the photon flux and at any given high iso is nearly the same for all the leading makes and for their different models for the same size sensor. And FF are about an ev higher than APS-C. The FM analysis has nearly an ev increase of the 90D over the 80D, putting it close to that of the 5DIV and 1DXII and leaping ahead of Nikon and Sony APS-Cs by more than you thinks the physics would allow