Weird PC Issues

[MasterSauceMan]

Hi, I've been having some weird issues with my PC. My PC randomly shut off one time, and ever since then I've been having weird issues, where in games my GPU will under clock it self, but never runs normal, until a game restart, even if the GPU is still running at the same temps from the underclock, to the restart and into the new game. It only eve happens on Warzone, I've never noticed the issue in any other games. Also, my PC will sometimes refuse to turn on when booting it up after shutting it down/restarting it. I'll press the power button and it will start the fans, the CPU Cooler RGB will light up, and the GPU fans spin. But it won't post, my mousepad, mouse, and keyboard will light up, but both of my monitors just show a black screen. Sometimes if I shut it down, it'll boot up fine, and sometimes it won't. I've tried re-seating the RAM and that yields the same results as shutting down and trying again, I've even taken everything out of my PC, cleaned everything, cleaned the motherboard, GPU, CPU, RAM, put new Thermal pads and paste on the GPU, and put new Thermal paste on the CPU, and re-seated every connection, with the same result. And sometimes the PC will lock up, and then fix it self but I'll have to restart the game I'm in as it only effects the game.

 

Motherboard: ASRock B450 Pro4

CPU: AMD Ryzen 7 2700

RAM: 2x8GB sticks of Cosair Vengence 2400MHz

PSU: Corsair RMX750x Fully Modular 750W PSU

GPU: XFX RX DD 580 8GB

1, 2 TB Western Digital Blue HDD

1, 1 TB Western Digital Blue HDD

and a Western Digital Blue 250GB M.2 SSD