Well, you are correct. Physically you can insert a 1x card into a 4x slot and it will work fine, but the 4x connector won't fit in a 1x slot (for a reason) and likely will not work even with the adapter. The link you provided comes up to a 404 Not Found HTML error for me but, I've heard about those risers before. Think about it this way. Your trying to plug in a 220 volt appliance into a 110 socket.