That was my first thought as well. When I took the fan off to move it over, I found out the second screw hole is missing. In the picture without the fan shroud, you can see one hole on the far right.... but that's it, the hole for the screw on the left side of the fan mount isn't present. I'm guessing Supermicro must have a different fan bracket that holds two fans. So, the next best thing was to add the cardboard.