Question My Gaming Pc Keeps Shutting Down Randomly, Even in Bios

Jul 15, 2019
Hello Guys,

First of all sorry for my English.

My computer keeps shutting down and restart instantly. Not only under heavy load also while in idle or even in bios.

Here is my setup;

Cpu : Intel Core i9 9900K
Cpu Cooler : Cooler Master MasterLiquid ML360R RGB
MB : Asus Rog Maximus XI Extreme
Ram: GSkill 16GB (2X8GB) Trident Z Rgb Led DDR4 3200Mhz CL16 (2 X Set -> Total 32GB)
SSD (Windows Installed) : SAMSUNG 1TB 970 PRO NVMe M.2 SSD
Graphics Card : ASUS ROG Strix GeForce GTX 1070
Psu : Thermaltake Toughpower Grand RGB 750W 80 Plus Gold
Case : Cooler Master C700P
Intake Fans (Front) : 3X Cooler Master MasterFan Pro 120 Air Balance
Exhaust Fan (Back) : Cooler Master MasterFan Pro 140 Air Flow RGB LED 140mm

As u you can see from the following pictures inside of the case is clean.
All of the components are new except PSU. It is also almost 2 years old.

I removed Graphics card from pc and put my monitors cable into motherbords hdmi slot, problem didnt solved.
I ran memtest for at least 2 hours. After 2 hour of testing, computer shut down again and to that moment there was no errors reported for the rams, problem didnt solved.
I disconnect my storage HDD's from system, problem didnt solved.
I checked is there any overheating problem maximum temp under heavy load, it is 75C for the cpu.
I trust Thermaltake Company but as i understand last suspect is PSU. Before replacing it, i would like to make sure if there is any other suspect.
Could you please help me to find which component in this system could be faulty?

Thank You All

I tried to give following links as photos, but site did not accepted it so i added as links. Sorry for that.

General View
General Inside View
Back View
Upside View
Front View
PSU View
Closer MB View
Closer Ram Sticks View