How Windows 11 Runs Natively on ARM64 Processors

Windows 11 runs natively on ARM64 processors, such as the Qualcomm Snapdragon X Elite, by compiling its operating system core, drivers, and native applications directly into the ARM instruction set architecture (ISA). Instead of translating code designed for Intel or AMD (x86/x64) chips through an interpretation layer, the OS interacts directly with ARM hardware. This native execution maximizes computational performance, dramatically improves power efficiency, and enables deep integration with specialized hardware such as Neural Processing Units (NPUs).

Direct Execution via ARM64 Core Kernel

At the foundation of Windows 11 on ARM is a kernel compiled natively for 64-bit ARM architecture (ARM64). When Windows runs on the Snapdragon X Elite:

• Instruction Execution: The Qualcomm Oryon CPU cores execute ARM64 instructions directly without translation. Instructions are processed in the native CPU pipelines, avoiding the performance penalties of dynamic binary translation.
• Memory Management: The Windows memory manager interfaces natively with ARM’s Translation Lookaside Buffers (TLB) and page tables, providing low-latency memory access across the platform’s unified memory architecture.
• System Services: Core Windows subsystems—including Windows Explorer, the Desktop Window Manager (DWM), Windows Defender, and core system utilities—are fully compiled for ARM64, resulting in instant responsiveness and lower background CPU usage.

Native Driver and Hardware Abstraction Layer (HAL)

Operating systems require drivers to communicate with physical hardware. Windows 11 on Snapdragon X Elite achieves full native support through dedicated ARM64 drivers:

• Adreno GPU and DirectX 12: The graphics driver interacts directly with DirectX 12 and Vulkan APIs via native ARM64 binaries, allowing graphics workloads to run without overhead.
• Hexagon NPU and DirectML: Windows 11 utilizes the Snapdragon X Elite’s 45 TOPS NPU natively via the Windows Copilot+ runtime and DirectML framework. This enables background AI tasks—such as live captions, image generation, and Windows Studio Effects—to run natively on the NPU without burdening the CPU or GPU.
• Power Management: The Windows Power Management framework communicates directly with the Snapdragon platform’s hardware-level power controllers, dynamically scaling CPU core clusters and sleep states to extend battery life.

The ARM64EC ABI for Seamless Interoperability

To bridge the gap between native performance and software compatibility, Windows 11 uses the ARM64EC (Emulation Compatible) Application Binary Interface (ABI).

ARM64EC allows developers to build applications containing a mix of native ARM64 code and legacy x64 code within the exact same process. For example, a heavy application can run its core engine natively at full ARM64 speed while still loading legacy x64 plugins that have not yet been ported. The OS manages transitions between native and emulated code transparently.

Prism Emulation for Legacy x86/x64 Software

For legacy applications that are not yet compiled for ARM64, Windows 11 on Snapdragon X Elite includes Prism, Microsoft’s next-generation dynamic binary emulator:

• Just-In-Time (JIT) Translation: Prism translates x86 and x64 instructions into ARM64 instructions in real time.
• Code Caching: Translated instruction blocks are cached in memory and disk so that frequently used code paths execute near native speeds on subsequent runs.
• Hardware Optimizations: Prism takes advantage of specific hardware features within the Snapdragon X Elite to accelerate the translation process, significantly reducing the overhead traditionally associated with software emulation.