Microsoft has started pushing a subtle yet impactful performance improvement to Windows 11 insiders through the May 26, 2026 optional preview update. KB5089573 introduces a Low Latency Profile that gives the Start menu, flyouts, and other shell components a near-instantaneous response feel by allowing the CPU to sprint in short, controlled bursts. It’s not a headline-grabbing redesign or a new AI feature, but for anyone who has felt the sluggish drag of a hesitant UI, this update is a quiet game changer.

The optional preview targets Windows 11 versions 24H2 and 25H2. While the rollout is gradual, users who manually check for updates can grab it now. The change is part of Microsoft’s ongoing efforts to refine the operating system’s feel, focusing on raw interactivity rather than just raw throughput.

What Is the Low Latency Profile?

The Low Latency Profile is a new power and performance policy that temporarily boosts the CPU frequency when specific UI interactions are detected. Think of it as a sprint button for the Start menu: the moment you press the Windows key or click the Start icon, the system briefly cranks up the processor clock to maximum speed, processes the input, renders the animation, and then returns to its normal power state in less than a blink.

This isn’t about making apps run faster or improving gaming framerates. It’s purely about perceived responsiveness—the time between your click and the visual feedback. Microsoft has been tuning the Windows compositor and input stack for years, but this is the first time the kernel’s power manager has been directly enlisted to prioritize UI latency over energy savings for such short, targeted intervals.

The mechanism relies on a combination of Intel Speed Shift, AMD Precision Boost, and Arm Energy Aware Scheduling. The scheduler detects a high-priority UI thread and immediately requests the highest performance state (P-state) available, holding it for just long enough to complete the frame. Early measurements from internal testing show Start menu open times dropping from 150–200 milliseconds down to 50–80 milliseconds on typical hardware—a difference the human eye can perceive as a crisp snap rather than a soft fade.

Why Start Menus and Flyouts Lag in the First Place

Modern Windows runs on a diverse range of hardware, from battery-conscious laptops to liquid-cooled desktops. To balance energy efficiency and performance, the processor constantly switches between low-power and high-power states. When the system is idle, the CPU drops to a deep sleep state to save power. Waking up from that state takes time—sometimes tens of milliseconds—which can introduce a perceptible delay when opening the Start menu or a flyout.

Complicating matters, Windows’ compositor uses hardware acceleration to render animations smoothly. If the GPU isn’t ready or the CPU hasn’t yet ramped up, frames get dropped, and the animation stutters. The Low Latency Profile short-circuits this by proactively requesting a performance boost the instant a qualifying input event occurs, ensuring both the CPU and GPU are already at full tilt by the time the rendering pipeline gets the command.

Flyouts—those little panels that pop out for Wi-Fi, Bluetooth, volume, and quick settings—are particularly sensitive because they often spin up helper processes on the fly. A typical flyout might need to query network status, check battery levels, or enumerate audio devices. The new profile gives those queries a head start, so the panel appears fully populated without the infamous empty-skeleton-then-population delay.

Technical Underpinnings: How CPU Bursts Work

KB5089573 adds a new set of power management hooks in the kernel and the User Mode Power Service. When the Shell Experience Host (the process responsible for Start, taskbar, and flyouts) receives a user input, it signals the power service via a new API: SetLowLatencyHint. This hint tells the CPU governor to temporarily override the current power profile and enter a high-performance mode with a default hold time of 100 milliseconds.

The 100 ms window was chosen carefully: it’s long enough to cover the entire interaction from click to fully rendered frame, including any slow I/O or buffer swap, but short enough that thermal and battery impact is negligible. If the animation completes earlier, the hint is cleared and the CPU drops back to its original state immediately.

On AMD Ryzen systems, the profile leverages CPPC (Collaborative Processor Performance Control) to request a short-duration frequency boost without locking the cores at high clocks for longer than necessary. On Intel platforms, it uses HWP (Hardware P-states) with a specific duty cycle that allows the processor to reach maximum turbo frequency and return to idle within single-digit milliseconds. Arm-based Windows devices use a similar mechanism tied to the LPI (Low Power Idle) framework.

Crucially, the boost is non-modal: other background tasks aren’t paused or throttled. The system merely draws a little more power for a fraction of a second. Microsoft’s own measurements indicate an extra energy consumption of less than 0.1% per Start menu open on a laptop, meaning even on battery power the feature should have no noticeable effect on runtime.

The Update Package: KB5089573

The optional preview update KB5089573 went live on May 26, 2026, for Windows 11 24H2 and 25H2. It’s not a security update; it’s a quality improvement release that will be rolled into the next month’s mandatory cumulative update for all users. As with all optional previews, it arrives as a non-security cumulative update (C release) and contains bug fixes and feature enhancements that have been validated in earlier Insider builds.

Alongside the Low Latency Profile, the update addresses several known issues, including a memory leak in File Explorer when viewing large folders, a credential provider hang on domain-joined machines, and a printing spooler regression that caused 10–15 second delays on certain printers. The full list is available on the Microsoft support site under the KB article.

Users on versions 23H2 and older are not receiving the Low Latency Profile, as the required power service infrastructure was only backported to 24H2 and 25H2. Microsoft has not announced plans to extend the feature to Windows 10, which remains in extended support until October 2025 and will likely not receive such performance features.

How to Get the Update

If you want to experience the snappier Start menu today, you can install KB5089573 manually:

  1. Open Settings > Windows Update.
  2. Click Check for updates.
  3. When the optional update appears, click Download & install.
  4. Restart when prompted.

The update is labeled as “2026-05 Cumulative Update Preview for Windows 11 Version 24H2 for x64-based Systems (KB5089573)” or the equivalent for 25H2 and ARM64. After installation, the Low Latency Profile is active by default with no configuration required. Power users wanting to verify can open Event Viewer and navigate to Applications and Services Logs > Microsoft > Windows > Kernel-Power, where they’ll see entries confirming the low-latency hints being triggered.

Real-World Impact: What Users Can Expect

Early adopters in the Windows Insider Program have been testing the profile for weeks, and feedback has been overwhelmingly positive. On a sub-$600 laptop with an AMD Ryzen 5 5500U, the Start menu went from a sometimes perceptible hitch to a confident pop. On a high-refresh-rate desktop with an Intel Core i9-14900K, the difference is less dramatic but still measurable, with flyouts appearing a few frames sooner.

The most noticeable improvement is consistency. Previously, a cold-open Start menu (when the process had been paged out) could take over 300 ms, especially on a machine with aggressive power savings. With the profile, that worst-case scenario is halved. The feature also helps mitigate the jank that sometimes occurs when opening Start while a demanding background task is running, as the boost overrides any ongoing throttling just long enough to complete the UI interaction.

For touch-first devices like the Surface Pro, the tactile impression is even more profound. Tapping the Start icon feels directly coupled to the on-screen animation, reducing the disconnect that can make touch interfaces feel “soft.” Microsoft’s internal telemetry already shows a measurable drop in Start menu abandonment (users who open Start and close it before it fully renders), which suggests the snappier response is making the UI feel more reliable.

Not a Magic Bullet: Known Limitations

The Low Latency Profile is not a remedy for all performance woes. It cannot fix fundamentally slow storage or an overloaded CPU. If your system is already pegged at 100% usage, the boost won’t help because the processor can’t go any faster. Similarly, if the Start menu’s content (like the “Recommended” section or web search results) is waiting on network requests, the boost doesn’t speed up the internet—it only ensures the CPU and GPU are ready to render as soon as the data arrives.

Some users in the Insider forums have reported that the initial build containing the feature caused a slight increase in fan noise on thin-and-light laptops, as the brief bursts pushed thermals just enough to spin up the fan for a second. Microsoft addressed this in later revisions by adding a hysteresis so that consecutive bursts don’t cascade into a sustained thermal ramp unless the user is rapidly and repeatedly opening and closing the Start menu—a usage pattern that is unlikely in normal operation.

Community Chatter and Feedback

While the windowsforum.com discussion on KB5089573 is still in its early stages, several themes have emerged. One user noted, “It’s subtle but once you notice it you can’t unfeel it. Going back to my old laptop without the update feels like it’s wearing lead shoes.” Another power user shared a quick PowerShell snippet to monitor the new ETW events, posting logs that showed Start menu latency dropping from 180 ms to 62 ms on a Dell Latitude 7450.

A few skeptics questioned whether the boost might cause excessive battery drain, but early power testing with Battery Report (powercfg /batteryreport) has shown no statistically significant difference over an eight-hour workday of normal use. One Systems Administrator expressed concern that the new power hints might interfere with Group Policy power settings in managed environments, but Microsoft confirmed that the Low Latency Profile respects administrator-defined power plans and will not override caps on maximum processor frequency.

Not everyone is thrilled, however. A minority of users on Reddit report that the feature introduces a micro-stutter when the boost ends and the CPU returns to its idle state, appearing as a tiny flicker in other open windows. Microsoft engineers have acknowledged the report and are investigating a potential fix involving a smoother frequency transition curve.

Looking Ahead: More UI Boosts on the Horizon

The Low Latency Profile is one piece of a broader initiative within the Windows shell team to make the interface feel as fast as a modern smartphone UI. Future updates are expected to extend similar boost heuristics to the taskbar overflow panel, the notification center, and the new desktop switcher animation. There’s also internal discussion about applying the concept to inking latency on touch-capable devices, where even a 10 ms improvement can make stylus input feel more natural.

For developers, Microsoft is considering opening up the SetLowLatencyHint API so that third-party applications can request brief performance bursts for critical UI moments—such as expanding a ribbon menu or launching a media playback control—without needing to permanently set their process priority to high. This would mirror Apple’s Grand Central Dispatch QoS and Android’s performance hints, giving Windows apps a more consistent way to signal urgency to the scheduler.

Summary

KB5089573 marks a meaningful step forward in Windows 11’s evolution from a powerful but sometimes sluggish OS to one that feels consistently tight and responsive. By intelligently borrowing a few hundred milliseconds of peak CPU performance for the interactions users perform hundreds of times a day, Microsoft has made the entire desktop feel more solid. The update is available now as an optional preview for Windows 11 24H2 and 25H2, and every user should consider installing it—if only to remember how good a truly snappy Start menu can feel.