PC has random frame drops & freezes in every program

[CheckTec]

Hey guys,
I made a post quite a while ago, for those who are interested, this problem is on the same Pc.
My PC randomly has extreme framedrops which last for about 10-15 seconds. Task Manager shows the CPU beeing weirdly stable at one exact percentage and GPU dropping to almost 0. I played a lot of Overwatch lately, the framerate there drops from up to 200 down to 0,5-2 but the drops happen in every program (and its always the whole computer which is lagging, sometimes even just on desktop with nothing open), they just happen more frequently in programs with higher performance requirements. The freezes also mess with the audio sometimes, making the pc completely silent or not register mic inputs anymore until I unplug and replug my headset.
The PC also sometimes doesn´t start the explorer.exe automatically. I boot up the PC and it shows me blackscreen instead of desktop. I then do strg+alt+esc -> task manager and start the explorer.exe manually but i would like to know why it doesn´t do that automatically...

Setup: 
 

Motherboard: asrock 990fx extreme3

cpu: amd fx 8120

gpu: Geforce gtx 460

Win 10

psu: combat power cp 750 plus

250Gb ssd, 500Gb hdd

ram: Corsair xms3 ddr3 2x8Gb 1600MHz

In difference to my old thread, the pc doesnt crash or restart on its own anymore, the new psu seems to have fixed that problem. But the freezes are still there and terrible. I am quite frustrated...




I am available for more info if you need it

I apologize for my probably a little weird english, i am a german.

 

[CheckTec]

Update:
I bought a gtx 1050 ti bc i wanted a new gpu and wanted to test for gpu issues. its not the gpu, bc the freezes still occur. altough it feels like they are a bit rarer now.

 

 

[CheckTec]

Hey guys, I figured out the problem. Theres an option in the  Bios named "AMD Application Power Management" which seemed to have messed up the CPUs Voltages or something. I turned it off and now it works.