The Energy Saver feature consists of several different options to prolong a computer's battery life by optimizing resource consumption.
All of the following features can be used only when a computer is running on a battery.
Parallels Toolbox for Mac
Hide non-active apps
Energy Saver hides active (idle) applications.
It makes the hidden applications go to the built-in Mac App Nap mode, where they consume very little energy.
Pause non-essential processes
Energy Saver pauses a number of system processes that are always running in the background.
These processes include Spotlight indexing, AppStore updates check and macOS updates check.
Having these processes paused significantly extends battery life.
Eject external devices
Energy Saver tries to eject all external devices that are connected to the Mac.
It includes hard disks and smartphones.
Note: Energy Saver may fail to eject the drives if they are in use (e.g. the data is being transferred to/from the drive or it's being formatted).
Pause Time Machines backups
Energy Saver temporarily prevents Time Machine from creating regular backups, but doesn't stop Time Machine backups if they are already in progress.
Since Time Machine backup process consumes a lot of Mac resources, having this option set drastically reduces overall energy consumption.
Note: Don't use this feature if Time Machine backups are critical to you.
Parallels Toolbox for Windows
Launch when on battery
Energy Saver activates once you unplug the PC from a charger.
Windows Power Plan settings are modified by enabling the following options.
Reduce screen brightness
Energy Saver automatically reduces screen brightness based the amount of battery charge left.
Enable CPU optimizations
Energy Saver limits CPU peaks preventing the computer from excessive resources consumption and overheating.
Enable video optimizations
The computer's video card is set to the fastest response. Therefore, video quality is reduced and Windows Aero affects are disabled for a longer battery life.
Enable other optimizations
When you enable this option, Windows power saving settings are mostly affected.
The computer screen and the connected external hard drives and external displays will be automatically ejected/disconnected when the computer is left idle for longer than a minute.