After upgrading win10, the fan rings and the fan rotates at a high power.

After upgrading Win10, the fan always turns around. At this time, you can consider changing the system cooling method. In the system default state, the heat dissipation mode is “active”, which means that the fan speed is increased before “reducing the processor speed” when the heat is relatively large.
If your computer fan continues to spin at high speed, consider changing it to "passive", meaning "lower processor speed before increasing fan speed" to reduce heat generation. Of course, this will have an impact on system performance, and we need to make some trade-offs.
This setting option is also available in Win7 and Win8.1 systems.
change the system cooling method steps:
Open the Control Panel - Power Options found in the back of the selected power plan click "Change plan settings";

click "Change advanced power settings";

here will change the way cooling system is "passive", can be determined