Based on my testing, this power throttle mechanism is triggered when the load is larger than a threshold. I think this mechanism is for the protection of the power system, since the power brick is only 150 watt, which is insufficient for a 8750h+1060 configuration. So, it is reasonable to give a 25w limit to the CPU when the load is too large.
However, I think the real problem lies in the limitation removal judge statement. I found I cannot remove this 25w limitation even if the load returns to a normal state. The only cure seems to be pressing fn+f5 for 3 times manually, when the load is lower than a threshold..
If I am correct, I hope Asus's BIOS engineers can make a smarter BIOS, which can quit the 25w limitation automatically and also rapidly..
By the way, my model is fx504gm-es74. Everything seems to be good unless I use CPU and GPU at the same time..
Hope my poster can help.