Sleep mode is a convenient feature of most computer operating systems, including Windows. It allows you to reduce system power consumption while preserving your work for quick continuation. If you need to take a short break while working, you don't have to shut down your computer completely; Instead, put it to sleep and quickly resume after the break.
But what exactly happens when you put your Windows system to sleep? Is your current work saved? What about Windows updates and active downloads? Let's find out!
What exactly happens when Windows goes to sleep?
The Windows sleepdown process
Once you select that Sleep When you select the option under Windows Power Options, your system goes through a series of transitions to go from a normal operating state to a power saving state. Here you will find out what is important when it comes to sleep mode.
- Save the active session in RAM: Windows begins the process by saving the current system state in RAM. All your currently active programs, processes, files and folders are stored in RAM, which can be quickly restored when the system wakes up.
- Turn off the components: Next, Windows turns off the CPU, GPU, display, and more to save power. External components such as USB drives and printers are also put into a power-saving state. However, the external mouse and keyboard remain active in standby mode to be able to wake up the system.
- Enter power saving mode: The system will now enter a power saving state in which only RAM and wake-up triggers are active. The activation triggers can be keyboard, mouse or network activity.
When the system wakes up, the process is reversed and all components are turned on. All previously opened apps, files and processes will appear exactly as they were before sleep mode was activated. Since the data is immediately available in the RAM cache, this wake-up process is almost instantaneous.
Is your work saved?
Yes, but only temporarily
The most important question you may have before putting your PC to sleep is whether all of your current work will be saved automatically. The answer is yes. When your system goes to sleep, the current state—everything you're working on—moves to random access memory (RAM). This allows you to continue your work exactly as you left it. It is similar to pausing a game and resuming it in the same state.
However, this is only temporary and is not the same as saving your work to disk. If your laptop's battery life is too low or there is a power outage while your computer is in sleep mode, it can cause Windows to shut down completely. When it turns back on, the RAM will be updated and all your unsaved work will be lost (unless the program itself has autosave).
Although Windows usually saves the entire state to disk in such cases, this may not work on desktops in the event of a sudden power failure. Therefore, it is best to save your essential tasks before putting Windows to sleep, especially if your device relies on external power or the battery is low.
Does Windows update in sleep mode?
And what about active downloads?
If you have a pending Windows update and a download in progress, both will pause when the system is in sleep mode. This is because most background processes are stopped in the sleep state.
However, Windows has a feature called “Wake-up timer“, which allows the system to wake up from sleep mode to perform certain tasks, including updates. For example, if an important Windows update is scheduled outside of business hours, your computer can be woken up to install it. After the update is complete, the system usually returns to sleep mode.
If you use a download manager when downloading, the downloads will stop immediately when the system sleeps. When the system wakes up, the download will resume automatically, or you can do it manually. However, if you download via a browser, the ongoing download may be aborted in some cases. You may need to restart the download when the PC wakes up.
How is sleep mode different from hibernation?
And when to use one of them
Many users confuse sleep mode and hibernation in Windows and sometimes use these terms interchangeably. However, there is a key difference. Unlike sleep mode, Windows does not store the current session in RAM when in sleep mode. Instead, your SSD or HDD will be used for the same process. This means that when you enable hibernation, your computer is completely turned off and uses almost no power. Your work stays safe even if the laptop battery dies or a sudden power outage turns off the desktop.
So that makes hibernation better than sleep and I should use it rather than sleep mode, right? In my opinion yes, but it depends. Because hibernation stores the session on the storage drive (as opposed to RAM), it may take longer than hibernation to restore the operating system state. However, if your device has an SSD instead of a hard drive, you may not notice much of a difference. In general, you can use sleep mode for shorter breaks, but switch to sleep mode for longer breaks.