Cosmos my friend, FastATA works per case sadly.
It worked on PIO4 ONLY with a speciffic HD of mine (in the past) and with every other HD or CF, PIO3 was the cap. (You can find a detailed thread of mine over EAB).
I never managed to go beyond PIO3 and that's why I decided to replace it with Idefix Express that's easier, and more compatible with all OSes.