WinUI 3 Performance: A Leap Forward

Microsoft has revealed significant performance enhancements in WinUI 3, including a 41% reduction in transient allocations and a 63% decrease in function calls during File Explorer launches, which will soon be available in the main development branch.

The WinUI team shared detailed benchmark results indicating that, for File Explorer, the number of transient memory allocations decreased by 41%, function calls dropped by 63%, and the time spent executing WinUI code was reduced by 25%. These improvements are part of Microsoft’s broader effort to make WinUI 3 the primary native UI framework for Windows applications, focusing on delivering more fluid and responsive user interactions.

The enhancements are expected to be integrated into the winui3/main branch shortly, with some updates also planned for WinAppSDK 2.x, though certain complex changes may be deferred to future releases due to potential risks. These optimizations include changes to default control styles and other core behaviors, which may require app developers to opt in to avoid compatibility issues.

Why It Matters

These performance gains matter because they directly impact the user experience of Windows applications, making them faster and more responsive. For developers, improved efficiency can lead to smoother app operation and potentially lower resource consumption, which is critical for both desktop and tablet environments. The move also underscores Microsoft’s strategic commitment to WinUI 3 as the future of native Windows UI development.

Background

WinUI 3 is Microsoft’s modern native UI framework for Windows, replacing WinUI 2 as part of the Windows App SDK. The transition aims to unify Windows app development, improve performance, and enable more fluid interactions. Prior updates have focused on stability and feature support, with this latest announcement emphasizing performance optimization, especially in core components like File Explorer and Notepad, which serve as benchmarks for overall system responsiveness.

“Our mission is to make WinUI 3 the best native UI platform for Windows experiences, and performance is at the heart of that effort.”

— Microsoft WinUI team

“These improvements will be brought out of the development branch soon, and you will see them showing up in the winui3/main branch.”

— Microsoft spokesperson

What Remains Unclear

It remains unclear how widely these performance improvements will impact all types of Windows apps, especially those heavily customized or relying on specific control templates. Additionally, some optimizations may require app developers to opt in, and the timeline for full adoption across the ecosystem is not yet specified.

What’s Next

Microsoft plans to release these improvements into the main branch shortly, with ongoing monitoring and potential further optimizations. Developers should prepare to evaluate these changes and opt in where necessary. Future updates may include additional performance enhancements and broader default settings for optimal app responsiveness.

Key Questions

When will these performance improvements be available to all users?

The updates are expected to be integrated into the winui3/main branch shortly, with deployment to the broader developer community following soon after.

Will all WinUI 3 apps automatically benefit from these improvements?

Most apps should see benefits, but some optimizations may require developers to opt in or update their app configurations.

Are there any risks or breaking changes associated with these updates?

Yes, some changes involve breaking modifications, such as adjustments to default control styles, which may affect app behavior if not addressed.

What should developers do to prepare for these changes?

Developers should review the opt-in options for performance optimizations and test their apps with the upcoming updates to ensure compatibility.