Aspire TC 1760 power supply. bought a 500w on the motherboard there is an 8 way plug but only 4 pins

hi all I have the above pc and wanted to put in a better graphics card nothing too drastic mainly used for laser cutting software but would like to play the ot game. I checked my power supply and it’s 180w so not much give there so I have bought a 500w on the motherboard there is an 8 way plug but only 4 pins are used, my new power supply has 2 4 pin plugs so could in theory plug them both in should I use 1 4 pin plug or both?

[Edited the thread to add issue detail]