Question about ASUS Prime Z270-P

It depends on what other components you are using. An appropriate graphics card needs more power. I would recommend a 550 watt power supply, because even a simple graphics card quickly consumes 150 - 200 watts, CPU and board another 100 watts, then it's almost not enough at 350 watts for SSDs, HDDs, fans, etc.... They all need power too. Spend CHF 10 - 20 more for a better power supply, you won't regret it...