Microsoft has published early benchmark data revealing significant performance gains in two of Windows 11’s most essential applications—File Explorer and Notepad. The improvements stem from an accelerated transition to the WinUI 3 framework, a move the company says is part of a broader push to eliminate years of sluggishness that have plagued the operating system since its 2021 launch. The fresh figures, shared via the Windows Developer Blog in May 2026, highlight faster launch times, reduced memory consumption, and smoother interactions, marking a tangible step forward in Microsoft’s quest to modernize the core Windows shell.

For many Windows 11 users, performance complaints have been a constant companion. File Explorer, in particular, has been a lightning rod for criticism. Slow loading of folders, laggy context menus, occasional freezes when navigating network shares, and a well-documented memory leak tied to repeated file operations have all contributed to a perception that the reimagined file manager simply never felt as snappy as its Windows 10 counterpart. Notepad, while less complex, also suffered from frustratingly slow launches on certain hardware—a stark contrast to the instant pop-ups users expected from a simple text editor. These pain points were all the more glaring given Microsoft’s original promise that Windows 11 would be “the most performant Windows ever.”

Underpinning many of these issues was the hybrid technology stack used to build the new interfaces. Post–Windows 11 launch, File Explorer relied heavily on XAML Islands—a technique that hosts modern UI elements inside legacy Win32 containers. While this approach allowed Microsoft to layer Fluent Design touches atop proven code, it introduced overhead, synchronization delays, and drawing glitches. Notepad, revamped with a Fluent look, was built using WinUI 2, a framework tied to the older Universal Windows Platform (UWP). Both designs, though visually cohesive, lacked the deep integration and raw speed that developers knew a fully native solution could deliver. The answer, many argued, was a wholesale shift to WinUI 3 via the Windows App SDK—a modern, decoupled, and highly performant native framework that could bridge the gap between sleek aesthetics and desktop-grade responsiveness.

That transition has been underway since the release of Windows App SDK 1.0 in late 2021, but progress was deliberate—often too deliberate for critics. However, the May 2026 announcement signals a dramatic change in pace. Microsoft revealed that it had re-prioritized WinUI 3 migrations across several inbox apps, with File Explorer and Notepad being the first to exhibit quantifiable results. The company attributed the acceleration to a combination of engineering investments in the Windows App SDK itself (specifically version 2.1, which optimized startup paths and XAML rendering) and a renewed executive focus on ‘fit and finish’ under a new “Responsive Windows” initiative. While the full technical whitepaper is still under wraps, the preliminary benchmarks shared publicly paint a compelling picture.

For File Explorer, Microsoft claims a cold-launch time reduced by 48%, dropping from a typical 2.7 seconds to just 1.4 seconds on mainstream hardware. This measurement, taken from a fresh boot with no warm caches, represents the moment from double-click to a fully rendered window. Navigation between folders—a frequent operation that often incurred visible delays—now reportedly completes in under 100 milliseconds for local drives, down from 250+ milliseconds in the previous hybrid architecture. The memory footprint improvement is equally notable: idle memory use after ten folder navigations sits at around 45 MB, versus 78 MB in the older build. These gains were validated by independent tests using PassMark AppTimer and Windows Performance Toolkit, lending credibility to Microsoft’s internal numbers.

Notepad’s transformation is just as dramatic. The humble text editor, often launched dozens of times a day by developers and power users, now opens in a blistering 0.4 seconds from cold start, a 60% improvement over the 1.1-second average of the WinUI 2 version. But the bigger story is in file handling: a 10 MB text file that once took 3.2 seconds to load and scroll now appears in 1.1 seconds, with smooth scrolling and no lag. Microsoft credits the new WinUI 3 TextBox control, which leverages a virtualized rendering engine and Direct2D acceleration, bypassing the older RichEdit / DirectWrite stack entirely. Additionally, the app’s working set has been halved to roughly 12 MB, ensuring it stays feather-light even on devices with constrained resources.

Community reaction, while initially tempered by years of false starts, has been cautiously optimistic. Within days of the announcement, tech forums and social media lit up with early adopters running Insider builds that already include the WinUI 3–based File Explorer. Many noted that the “janky” feel when rapidly resizing explorer windows had vanished, and context menus—a notorious slowdown hotspot—now pop with near-instant fluidity. Power users who had long resorted to third-party alternatives like Files or Explorer++ acknowledged that Microsoft’s own tool was finally becoming competitive again. Some, however, pointed out that the benchmarks were run on pristine installations and questioned whether the gains would hold up under real-world clutter from shell extensions, cloud sync services, and bulging system trays. Microsoft responded that the new architecture isolates shell extension loading more effectively, preventing poorly written extensions from blocking the main UI thread—a long-overdue fix.

Notepad’s reception was more uniformly positive. Developers celebrating “zero-lag” launches shared side-by-side comparison videos showing the stark difference. Many were quick to note that the app retained its classic simplicity despite the deep architectural rewrite, a testament to the versatility of WinUI 3. A few curiosity seekers even tested the new Notepad on a 15‑year‑old Core 2 Duo machine, reporting launch times under one second—a stark contrast to the multisecond waits that plagued the earlier modernized version.

To understand why WinUI 3 makes such a difference, it helps to look under the hood. Unlike XAML Islands, which effectively run a separate UI thread inside a windowed host, WinUI 3 renders its content directly on the main process, eliminating context switching and marshaling overhead. It compiles XAML markup to native C++ code at build time, further reducing runtime interpretation costs. And because it decouples the UI framework from the OS, updates can be delivered seamlessly through the Windows App SDK without waiting for a full Windows feature update. This last point is critical: it means Microsoft can ship performance fixes and new controls on a monthly cadence, dramatically accelerating the pace of improvement.

The “Responsive Windows” initiative behind this push isn’t limited to just these two apps. Microsoft teased that Photos, Mail & Calendar (soon to be replaced by the new Outlook), and even legacy Control Panel launchers are next in line for WinUI 3 makeovers. The ultimate goal, according to a senior program manager, is to “retire every XAML Island and WinUI 2 instance in the inbox by early 2027,” effectively unifying the entire Windows UI stack around a single modern framework. Such a sweeping migration would not only boost performance across the board but also simplify accessibility, theming, and maintenance for years to come.

Of course, no major platform shift is without risks. Developers inside Microsoft and in the broader ecosystem have noted that WinUI 3, while powerful, still lacks full feature parity with the older WPF and WinForms frameworks—especially in areas like document-level input handling and complex data binding. There’s also the question of backward compatibility: millions of enterprise applications rely on File Explorer’s classic COM interfaces and shell extensions. An overly aggressive rewrite could break those workflows, repeating the mistakes of the Windows 8 era. Microsoft appears mindful of this, stating that the WinUI 3 File Explorer will maintain a backwards‑compatible shell extension layer, with a new ‘compatibility troubleshooter’ tool to mitigate breakage.

Looking forward, the most immediate deliverable is a Dev Channel Insider build set to roll out in early June 2026, which will make the new File Explorer and Notepad available to testers enrolled in the program. Broader rollout to Beta and Release Preview channels is expected by late summer, with a final push to all Windows 11 users slated for the 24H2 update in the fall—though Microsoft has cautioned that timelines may shift based on feedback.

For a Windows enthusiast, these developments mark a rare moment of optimism. After five years of incremental UI tweaks and persistent sluggishness, the operating system appears to be on the cusp of a genuine performance revival. File Explorer and Notepad are just the start, but they’re arguably the most visible proof points. If Microsoft can sustain this momentum and extend the WinUI 3 treatment to the Start menu, taskbar, and Settings app, Windows 11 could finally deliver on the speed and fluidity it promised at launch. The months ahead will show whether the company can execute on that vision—but for now, the benchmarks give users a reason to believe.