Looking to get extra performance out of your MacBook, battery life be damned?
Check outMac High Power Mode.
How Do You Turn on Power Saving Mode on a Mac?

ClickBatteryin the left-hand sidebar.
Check the box next toLow power modeto switch on the power-saving mode.
To do that, clickPower Adapterinstead ofBatteryin step 4.

What Is Low Power Mode?
Low power mode is a more efficient way for a MacBook to operate.
The company hasn’t made similar claims about how the mode impacts MacBook battery life.
FAQ
To deactivate low power mode, return to theBatteryscreen in System Preferences and uncheck the box.
The Apple Watch’s version of low power mode is called “power reserve.”
Once it’s on, it’s possible for you to deactivate it by pressing and holding theside button.