Question Computer Black screen and after few seconds rebot or I need to reboot it

[ImpossiblePower]

When I'm gaming sometimes my screen just goes black and I need to reboot my PC. What can be wrong and how to check which hardware problem is. I stress tested GPU for 1 hour and half and max temperature is 60 C. HDD is 100 % health. CPU is fine too.
GPU: GTX 1050 TI 4GB Strix
CPU: Ryzen 5 1600 3.2 GHz
Motherboard: ASROCK AB350
2x8 HyperX RAM 3000 MHz

 

[Lutfij]

Make and model of your PSU and it's age? BIOS version for your motherboard, at the time of writing? A reboot for the entire system only when the system is taxed can indicate either a thermal issue(overheating) or an issue with a faulty or failing(lackluster) PSU.

 

[ImpossiblePower]

PSU : CoolerMaster Masterwatt 700 W https://www.coolermaster.com/catalog/power-supplies/masterwatt-lite-230v/masterwatt-lite-230v-700w/. 2years old PSU . When I'm gaming in this case was VALORANT , my game keep frezzing like every few minutes and then just black screen and reboot.
BIOS Version/Date American Megatrends Inc. P3.20, 9/5/2017