Friend of mine has a prebuild 5600g system and it is constantly overheating with bf6, due to the high temperature it was downclocking itself.
We needed to upgrade the CPU Cooler and to undervolt the CPU slightly since the prebuild case is way too small.
In addition we added two more case fans because the heat of the dedicated GPU + the CPU was too much for the small case.
So in order to see if your System suffers the same problem would you please try this Software "HWMonitor", it can Log Temp & Clocks.
Tools -> Start Recording
Tools -> Stop Recording
It should give you a CSV File which we can hopefully analyze.