I have a Cooler Master Elite Power - 460W Power Supply. It only has one 6-pin PCI-e cable. I am thinking about getting a new graphics card, specifically the ATI 6870. The card requires two 6-pin PIC-e power cables. Is it a good idea to buy a 4-pin to 6-pin adapter and use the one 6-pin cable with a 4-pin molex turned into a 6-pin to power the graphics card? I don't want to overload the PSU or risk making the computer unstable.