Well thanks everyone for the replies. I decided to buy some unpowered cables and molex adapters. The mod on forum doesn't look too difficult and what I spent in total is less than two units from hashratestore.com. I'm still skeptical whether power is necessary as the three cards I have on the motherboard are working swell and not burning out anything as is. Better safe than sorry, I guess.
Power probably won't be necessary, but if the board blows you know why. Where did you end up buying them from? If you bought the ones on ebay they are going to take a long time to ship from HK
