AtlasOS is a redesign of Windows 10 for gamers, enabling smooth gameplay, higher FPS, and lower input and latency even on low-end PCs.

AtlasOS has key features including reducing the number of processes running in the background inside the system to reduce CPU activity and reduce system latency. To increase storage capacity on AtlasOS, the developers have removed unimportant features of Windows 10.
AtlasOS also focuses on privacy, open source transparency. AtlasOS ISO file is quite small in size when compared to the official Windows ISO file.
AtlasOS (0.5.2) RAM usage - the latest version has cut the number of background processes from 185 to about 35 to only 600 MB, a significant reduction compared to Microsoft's official Windows 10 version 21H1, 1.5 GB. AtlasOS latency has also decreased from 3.09s to 2.55s.

According to the project's official GitHub page, the developers have removed all "negative Windows drawbacks" that could negatively affect gaming performance on Atlas.
Additionally, AtlasOS also disables many security features described as "bloatware" and disables mitigations for hardware security flaws in Intel (and AMD) CPUs such as Spectre and Meltdown, Trusted Platform Module (TPM), BitLocker, Windows Defender, Voice Recognition, Restore Points & System Reset.
Because it wants to optimize the operating system just for gaming, AtlasOS offers fewer features, less compatibility, and less security than Windows 10. Therefore, AtlasOS will not be a great choice for ordinary users.
If interested, you can download AtlasOS to try and experience it.