Troubleshooting imac turning off in Xplane 11

[dimme]

I have a 2019 i9 5K imac w/ a vega gpu and 40 MB of ram (running the latest OS and updates). Once in a while while running xplane 11.5r3 my imac will turnoff. When I run a query in the terminal for shutdown reasons it come back code 0 which is power disconnected. I have looked at the os log files and temperatures in istat and don't really see any problems. I have tried various settings in Xplane such as lower resolution and it will still turn off. What I like to try nest is to limit the CPU to 80 or 90% but I not sure how to do that or even if it is possible. Does anyone know how to do that or have other ideas how to solve this problem. Also net time this happens I be looking at the xplane log file which I have not done yet. Any advice appreciated, thanks

 

[Flint Ironstag]

Might check your power delivery from the wall.