Introduction

Microsoft is preparing a significant update for Windows 11 on ARM64 devices with the upcoming version 24H2. This update primarily focuses on enhancing app performance and compatibility through a reengineered x86 emulator named "Prism," offering a much-needed boost for legacy ARM devices running Windows. This article explores the technical details, background, and implications of this update for both users and the broader ARM ecosystem.

Background and Context

Windows on ARM has faced a challenging journey marked by limited app compatibility and middling hardware adoption. While ARM processors have dominated mobile and are making significant strides in laptops (notably with Apple's M-series), Windows on ARM platforms have yet to fully realize their potential due to these hurdles.

Microsoft's collaboration with Qualcomm for Snapdragon X series SoCs, especially the upcoming Snapdragon X2, signals its commitment to improving ARM performance. The introduction of the Prism emulator marks a critical architectural advancement designed to improve the execution speed and compatibility of x86 legacy applications on ARM devices.

What Windows 11 24H2 Brings to ARM Devices

Enhanced Prism Emulator

The Prism emulator is the centerpiece of this update. Designed to replace the previous x86 emulation layer, Prism is optimized specifically for ARM64, delivering faster and more reliable interpretation of legacy x86 software. Early benchmarks indicate performance improvements ranging from 7% to 15% on older ARM laptops.

Automatic Super Resolution (Auto SR)

Another highlight is the integration of Windows’ AI-powered video upscaling (Auto SR), designed to enhance textures and improve visual fidelity in games. However, this feature requires more advanced hardware and is unavailable on entry-level Snapdragon SoCs such as the Snapdragon 7c+ Gen 3.

Legacy Device Focus

Windows 11 24H2 targets not only new ARM64 hardware but also extends performance improvements to older devices. For instance, tests on the Samsung Galaxy Book2 Go, a Snapdragon 7c+ Gen 3 powered fanless notebook, show measurable gains in CPU-intensive benchmarks like Cinebench R23 and Geekbench 5.5.

Benchmark Highlights on Legacy ARM Devices

  • Cinebench R23 (Single-Core): Improved by 10% (from 358 to 393 points)
  • Cinebench R23 (Multi-Core): Improved by 9% (from 1555 to 1698 points)
  • Dota 2 Low Settings (FPS): Improved by 7% (from 33.7 to 36.2 fps)
  • PCMark 8 (Work Score): Improved by 3% (from 1609 to 1656 points)
  • 3DMark FireStrike Physics: Improved by 5% (from 4826 to 5073 points)

Despite these gains, GPU-heavy and gaming performance improvements remain moderate, and the update does not transform entry-level ARM devices into gaming powerhouses. However, daily tasks, productivity, and media consumption are notably smoother.

Installation and Compatibility Notes

The update process has reported some challenges, with users experiencing initial installation failures and hardware component initialization issues, such as WiFi and 5G modem driver problems, which require manual updates post-installation. Microsoft recommends using wired Ethernet connections during installation to avoid such issues.

Implications and Impact

For Users

  • Improved Longevity: Older ARM devices gain extended viability with enhanced app compatibility and faster execution.
  • Better Performance for Everyday Tasks: Improved CPU performance makes web browsing, office productivity, and light media processing snappier.
  • Limited Availability of Advanced Features: Hardware constraints mean that not all users will benefit from features like Auto SR.

For Developers and Microsoft

  • Boost to Windows on ARM Ecosystem: Enhanced emulation encourages developers to support ARM64, potentially expanding the native ARM app ecosystem.
  • Strategic Platform Unification: Updates like the Germanium platform aim to unify Windows 11’s core platform, simplifying updates and increasing stability across various hardware.

For the Industry

The progress heralded by the Prism emulator and enhanced ARM support aligns Windows more closely with ARM’s growing prominence in personal computing. This update addresses one of the long-standing challenges with Windows on ARM—legacy app performance—and signals Microsoft’s intent to support ARM devices in the long term.

Technical Overview of the Prism Emulator

The Prism emulator is a reengineered x86 emulation layer optimized for ARM64 architectures. Utilizing more efficient dynamic recompilation and improved CPU scheduling tailored to ARM cores, Prism reduces overhead and compatibility issues associated with older emulators. This results in lower latency app launches, smoother execution of legacy software, and improved resource utilization.

Conclusion

Windows 11 24H2 exemplifies Microsoft's commitment to revitalizing the ARM64 platform by addressing critical performance bottlenecks through the Prism emulator and other platform improvements. While it does not turn legacy ARM devices into cutting-edge gaming machines, the update delivers tangible improvements making ARM-based Windows laptops more practical and future-proof.