Samsung
Turn Power Saving Mode On or Off auf Samsung
Power saving mode reduces battery drain by restricting what apps can do while your screen is off or you are not actively using them. It blocks background data traffic, stops apps from requesting your location, and on many models it also lowers CPU speed or disables Always On Display to save extra charge.
This is different from a full restart or clearing an app's cache: it does not fix crashes or freezes, it only changes how much power the system allows apps to use in the background. If an app misbehaves even with the screen on, Power saving mode will not help and you should check that app's own battery settings instead.
Menu path to turn Power saving mode on or off
Open Settings ➔ Battery and device care ➔ Battery ➔ toggle Power saving mode on or off.
Once enabled, you can usually still adjust how strict the mode is, for example whether it limits performance, dims the screen, or restricts specific apps individually. Switch it off from the same screen when you need full performance or Always On Display back.