Question: how much power supply do i need for gtx 1080?
Answer: Here is Guru3D's power supply recommendation: GeForce GTX 1070 / 1080 - On your average system the card requires you to have a 600 Watts power supply unit. GeForce GTX 1070 / 1080 SLI - On your average system the cards require you to have a 850~900 Watts power supply unit.