Introduction

The Windows on ARM platform has historically faced challenges in performance, app compatibility, and real-world usability, leaving many users skeptical about the ecosystem’s viability. However, the release of Windows 11 version 24H2 in mid-2024, paired with Qualcomm’s Snapdragon X series SoCs, has injected fresh vitality into the platform. A pivotal highlight of this update is the introduction of the redesigned "Prism" emulator, which significantly enhances legacy x86 app performance on ARM hardware.

Background: Windows on ARM and Its Trials

Windows on ARM was Microsoft's ambitious attempt to blend energy-efficient ARM architecture with the full Windows experience, targeting ultra-portables and always-connected PCs. Despite promise, early devices struggled due to crude x86 emulation, limited app support, and underwhelming hardware performance relative to Intel and AMD.

Qualcomm's Snapdragon processors, particularly the Snapdragon 7c and later X series, have incrementally improved the ARM Windows experience. But performance bottlenecks, especially in running legacy Windows applications compiled for x86, persisted.

What Windows 11 24H2 Brings to Legacy ARM Devices

The Prism Emulator

Central to the 24H2 update is the "Prism" x86 emulator—a reengineered compatibility layer that accelerates and smooths the execution of non-native Windows applications. Early benchmarks show performance uplifts in the 7-15% range on older ARM devices like the Samsung Galaxy Book2 Go, a Snapdragon 7c+ Gen 3-powered fanless laptop.

Automatic Super Resolution (Auto SR)

This AI-driven video upscaling feature enhances gaming graphics and video textures but requires more powerful hardware, such as Snapdragon X series chips. Entry-level Snapdragon SoCs found in legacy machines cannot leverage Auto SR due to hardware limitations.

Benchmark Insights on Legacy Devices

In performance tests comparing Windows 11 23H2 and 24H2 on the Galaxy Book2 Go:

Benchmark 23H2 Score 24H2 Score Performance Gain
---------------------- ------------ ------------ ------------------
Cinebench R23 (Single) 358 393 +10%
Cinebench R23 (Multi) 1555 1698 +9%
Dota 2 (Low settings) 33.7 fps 36.2 fps +7%
PCMark 8 (Work) 1609 1656 +3%
3DMark FireStrike Physics 4826 5073 +5%

The improvements are most pronounced in CPU-intensive tasks, validating the Prism emulator's optimization. GPU and gaming performance see smaller gains, confirming hardware ceilings remain a constraint.

Technical Challenges and Installation

Users report that upgrading to 24H2 is not always straightforward. Initial installation attempts on legacy devices have encountered Blue Screen of Death (BSOD) errors and post-installation issues like missing drivers for WiFi, 5G modem, and GPU. Workarounds typically involve leveraging Ethernet connections for driver updates and manual troubleshooting.

Implications for Users and the Ecosystem

  • Extended Viability: Legacy ARM device owners can enjoy a noticeable speed boost without new hardware purchases.
  • Incremental Improvements: While not transformative, the update enhances everyday productivity and responsiveness.
  • Feature Limitations: Hardware-imposed limitations prevent some advanced features (e.g., Auto SR) from running on older devices.
  • Upgrade Caution: Non-expert users may face hurdles during installation, advising caution or professional assistance.

For the broader Windows on ARM ecosystem, this update signals Microsoft and Qualcomm’s commitment to improving the platform’s usability and performance, potentially encouraging more developers to optimize ARM-native applications.

Conclusion

Windows 11 24H2, through its Prism emulator and targeted performance enhancements, offers tangible benefits to legacy ARM laptops, enhancing their capability and longevity in the face of rapidly evolving PC hardware landscapes. While not a panacea for all ARM-related performance issues, it provides a meaningful uplift for existing devices, deferring costly upgrades and improving user experience.

References: