It seems you know more about mining equipments, see I have a 6pin to 8pin cable and it works like every other 8pin connectors from powers supply, I don't know why many are saying the connector can start fire or some thing, here is what I used and it works fine

Some people like to live on the edge, others like to be comfortable. fact that graphic card COULD draw 150W through 6-pin connector doesn't mean it will...but why test it?