psu restart

my pc spec: r9 285 2gb i5 3570 ram 6gb psu some random Zito 500w psu i asume thats some 10-15$ psu monitor 1680 so when i play some more intense games like Kingdom Come Deliverance, BF4 etc. when pc cpu temperature reaches around 70 after 2 min or so after it reached that temp my pc restarts...

My setup has a HyperX Cloud Revolver hooked up to the pc through an Asus Xonar U3 sound card. The issue is that both with and without the sound card, the sound from my pc (eg: games and music) goes through my mic and can be heard by people I chat with on discord. I've had this issue for a while...