I found seven WHEA- Logger Events with the Title "Fixed Hardware Error" from my CPU Core. But this was four days ago where my VCore Voltage was still set to 1.13V or 1.14V and prime crashed with these settings. I set the VCore Voltage to 1.16V yesterday and since then I didn´t get any WHEA-Logger Event happening. I will keep an Eye on my Event viewer the next few days.
Just for knowledge: What if the WHEA- Logger Events come back? Increasing VCore? (Sorry for my not so good english btw.)