CPUs are a bit like office buildings, and 100% and 0% CPU usage are a bit like saying the building is Occupied or Unoccupied. It doesn’t tell you much about the operations within.
CPUs have many internal components, which may or may not be in use while it is occupied. A good example of this is a program that gets stuck in an infinite loop will stall and consume 100% CPU, but not make much heat because it’s like only using the lobby of the building. Doing just one thing.
On the other hand, when the CPU fires up AVX-512, the CPU has to downclock aggressively to have enough power for that workload. It’s like if you crammed thousands of people into two floors - you’d have to be mindful of the HVAC needs of those floors, at the expense of other tasks/floors, or everyone there would overheat.
Because of this, no two “100% use” workloads are identical. I am reminded of a graphics driver update a few years back that nVidia put out, which improved one game’s FPS by a whopping 40%. In the immediate aftermath, the forums were plagued with users complaining of crash issues. The drivers did such a better job keeping the components of the GPU utilized, it resulted in too high of temperatures and too high of power draw, causing those crashes. Some power supplies and manufacturer GPU cooling solutions were not up to the task. The solution ended up being underclocking the GPUs with MSI Afterburner.
You think you do a good job by optimizing your software to more fully use your office building, and suddenly nobody can run it because of those crashes! Tsk tsk!
I would start to get to the bottom of it by graphing RAM, CPU and GPU usage. Use programs like RAMMap and MSI Afterburner. Dump the data that you can to a file. I have seen it where the Task Manager thinks RAM is 60% in use, but RAMMap adds up to 97% in use, so more accurate accounting of memory could reveal a point of failure. My main workstation has 128GB of RAM, for good measure.
Graphing CPU, GPU usage, temperatures, boost levels and voltages could also reveal something. A lot of computers will shut down if components exceed 90-100C, so keep that in mind.
Good luck with the detective work ahead of you!