Windows 10’s S mode helps you run a lighter version of the operating system. It’s best used for computers that might not have powerful CPUs and other hardware specs, as well as if you know you don’t need any features that come with the full version of Windows.
Some suggest that S mode was meant to be a competitor to the popular ChromeOS that is proving to be very popular among students in the United States, though Microsoft has not spoken about that.
One of the things that Windows 10’s S mode is good at is security. All the apps that you can install with S mode come directly from the Microsoft Store, where Microsoft makes security of the utmost importance. Microsoft also claims that the Microsoft Edge web browser offers better protection against malware such as phishing and socially-engineering attacks compared with Google Chrome and Mozilla Firefox.
S mode still comes with Windows Defender antivirus, and if you turn off S mode, your computer will still be protected by Windows Defender. Microsoft says the way Windows Defender works in S mode may be different, but you can rest assured that Windows always has your back, by default, no matter what mode you’re in.
Also worth noting is that if you have another third-party antivirus in mind, Microsoft lets you install it. And as soon as you do, the Windows 10 OS will automatically detect it and turn off its Windows Defender antivirus; there’s no need for you to turn any antivirus on or off.