Im having the same issue cpu rpm 0 with arctic freezer pro v2. This is my second mobo. Asus sent me a new one under warranty because of what the tech said was a faulty reading since my cpu fan was working and my temps were in check. I wonder if it is the latest bios, I might try to flash the bios to a earlier version
Is your cpu fan connect into the top or bottom fan header? The bottom header is for the main cpu fan, top is for a 2nd one.