So my graphics cards are Geforce GTX 1060 1 (6) slot and a Geforce GTX 1080 2 (8) slots and my PSU only has 2 (8) pin PCIE connectors. Do I need to buy a new PSU yo fill all the slots on my graphics crad
Well, you didn't mention what your PSU is or its power rating. However, if it doesn't have enough PCIe power connectors, it very likely isn't going to be capable of delivering enough power for the GPU you are using. You could use a splitter cable (8 Pin female connector on one end that splits to two 6/2pin male connectors at the other end) on the end of one of the PCIe cables, but you do run the risk of overloading the rail that feeds that connector, that poses a safety risk.