AtlasOS Documentation

Current versions of AtlasOS (v0.3 and later) include several security improvements and support for standard Windows security features, including:

• Windows Update support
• Windows Defender support
• User Account Control (UAC) enabled by default
• Core isolation support
• Improved transparency regarding security features

After installing AtlasOS, you can optimize your system performance by following hardware-specific post-installation steps. The recommended order of operations is:

1. Enable XMP/DOCP: To ensure your RAM is running at its rated speed.
2. Enable Resizable BAR: If your GPU and motherboard support it, to improve graphics performance.
3. Update BIOS/UEFI: Only when necessary for stability or compatibility, and always after backing up important data.

Resizable BAR (Base Address Register), referred to as Smart Access Memory (SAM) by AMD, is a hardware feature that optimizes communication between the CPU and GPU.

How it works:

• Traditional Method: The CPU is limited to accessing the GPU's VRAM in small 256MB chunks, requiring many sequential transfers.
• Resizable BAR Method: The CPU can access the entire GPU frame buffer concurrently. This allows for larger, more efficient data transfers of textures and shaders, reducing the time the graphics card spends waiting for assets.

AtlasOS permanently removes certain Windows components that cannot be re-enabled without a full Windows reinstallation.

Permanently Deleted Component:

• Smart App Control: This is disabled because it sends significant data to Microsoft and requires optional diagnostic data. It can also cause severe performance slowdowns if Windows Defender is disabled. Once disabled, it cannot be reinstalled on the current Windows instance.

When performing an upgrade via AME Wizard, most of your environment is preserved:

• Preserved: All user files, installed apps, and most AtlasOS tweaks.
• Known Limitation (Version 0.4.x → 0.5.x): Upgrading from version 0.4.x to 0.5.x does not carry over the Atlas Folder configuration (including General Configuration, Interface Tweaks, etc.). You must re-apply these settings manually after the upgrade.
• Note: This limitation does not apply to upgrades from 0.5.x to later versions.

AtlasOS is designed for enthusiasts seeking to improve Windows privacy, performance, and ease of use through a stable, compatible, and usable modification.

Do not install AtlasOS if:

• You are using a computer that you do not fully own.
• You are unwilling to perform Windows troubleshooting.
• You are unwilling to perform a full reinstallation of Windows.

When setting up AtlasOS, you have the choice between using a Microsoft account or a local account for your primary Windows login.

Recommendation: Use a local account.

AtlasOS recommends using a local account for your main Windows user profile to maximize privacy. Using a local account helps minimize data collection and telemetry by avoiding the direct link between your device usage/diagnostics and your personal Microsoft account profile.

Key distinction:

• Main Windows Login: Use a local account to align with AtlasOS privacy goals.
• App-specific usage: Use your Microsoft account within the Microsoft Store or specific apps (like Xbox) to access services and subscriptions.

To ensure system stability and performance, only install the drivers required by your hardware. Essential drivers typically include:

• GPU/iGPU (Graphics)
• Audio
• Wi-Fi
• Bluetooth

If you are unsure which specific driver a device needs, look up your hardware components directly to find the manufacturer-specific drivers.

AtlasOS is designed to provide power users with the ability to customize the balance between security and convenience. It does not enforce a single security state; instead, it allows users to freely toggle features such as Windows Defender, mitigations, and automatic Windows updates.

Atlas provides warnings about the risks of disabling security features through:

• Pre-install configuration prompts
• Official documentation
• Atlas folder scripts

Users can change security settings at any time post-installation.

Several Windows features are disabled in AtlasOS to improve privacy and performance. These require manual tweaking to re-enable and are not officially tested by the Atlas team.

Disabled Components:

• Telemetry: Includes Windows Error Reporting, CEIP, and other telemetry policies. Atlas provides an option to toggle telemetry components specifically for troubleshooting.
• Microsoft Account Syncing: Various syncing features using a Microsoft account are disabled.
• Advertisements and Tips: General Windows advertisements and tips are removed.
• Context Menus: Uncommonly used context menus are disabled.
• Activity History: Windows activity history is disabled.