If you are on a Laptop and it does have a dedicated Graphics card from Nvidia or AMD, then open the Control Panel and switch the default Graphics Processor to AMD/Nvidia instead of the Integrated one. In the Windows Power Settings Icon on the Taskbar, change the Power Mode to Best Performance. So, connect the power cord to your laptop and move to the next step.
If you have a dedicated GPU, then without external power, it won’t perform at its best.
If you’re using a Laptop, you shouldn’t be gaming without external power supply. The steps 1, 2 and 3 are only for Laptop Users, so the PC users can ignore them and move directly to the Step 4.