i currently have a thermaltake toughpower 600w (primitive version with 2X6 pcie pin) and i have a basic system with core i5 2nd gen. now the said card(ati radeon r9 290x/290) requires 1x8 pin and 1x6 pin which i dont have. hereby i can use a molex to 8 pin converter or 6 pin to 8 pin converter. which should i prefer? is there any cons of doing so? seeking for expert advice