Microsoft Proves Modern WinUI Can Outperform Legacy Code

Microsoft has been working on modernizing Windows for years, and one key area of focus is migrating legacy features to its WinUI framework. This effort aims to bring a more modern look and feel to Windows, but critics have argued that it would come at the cost of performance.

One such feature is the Run dialog (Win+R), which has been redesigned using WinUI 3 and C#. The new version retains the familiar experience while supporting dark theme and modern icons. But what's impressive is that it's actually faster than its legacy counterpart, thanks to Microsoft's focus on performance.

According to internal benchmarks, the new Run dialog takes a median time-to-show of just 94ms, compared to 103ms for the old version. This represents an improvement of around 8.7%.

The company credits its use of .NET AOT (Ahead-of-Time compilation) for this boost in speed. By compiling the code ahead of time instead of using the normal JIT compiler, Microsoft has managed to achieve the 'blazing speed of native code' while retaining C# and WinUI 3.