it is normal that the computer gaming will be inferior when not connected to the AC power source, this is cause by the power settings in windows which by default is set to "balanced". this can be changed (see below) but you must understand that changing it to be Non-AC gaming performance will drain your battery very quickly.
in search bar of your windows type " change power" you should find change power settings, select that.
then change the setting from balance or power saver to "performance" as shown below.
reboot computer
happy gaming.