The new Expanded Prefetch Range improves Chromium performance on Windows 11

Since switching to Chromium in late 2018, Microsoft has actively contributed to the new engine for a better Edge experience. Recently, the Redmond giant worked with Google for Chromium browsers to benefit from and use the expanded Application Launch Prefetch range (APLF) available on Windows 11 21H2 or later.

The /prefetch parameter is a key component in how browsers handle file access patterns for their processes. It helps differentiate the behavior of processes with the same name, providing a way to optimize and streamline how various tasks are carried out.

Previously, the /prefetch: N range used on the process command line was in the range of 1-8 (can be seen in the Windows Task Manager). Microsoft shared that Chromium browsers using the 1-8 range leads to less optimal APP launch Prefetch (ALPF) behavior. However, they should use 1-16 for Windows 11 21H2 and later versions.

What are the benefits of Prefetch range expansion?

Improved Process Separation: The expanded /prefetch range allows for better separation of processes, which is particularly beneficial for tasks like rendering web pages and handling utility processes in the background.

Enhanced Performance: With a broader range, the browsers can optimize how they prefetch and access files, potentially improving overall performance.

Adaptation to Modern Operating Systems: As the change is specifically targeted at Windows 11 and later versions, it ensures that these browsers are optimized to work seamlessly with the latest features and improvements in the operating system.

Optimizing Resource Usage: The adjustment in the /prefetch parameter range allows browsers to use system resources more efficiently, contributing to a smoother user experience.

In case you didn’t know, the Prefetch range is not specific to Chrome or other Chromium-based browsers. It is a feature of the Windows operating system that can be leveraged by any application that runs on Windows 11 and later.

The change was added to the Chromium branch, and we noticed that Microsoft tested the Edge browser with the Expanded Prefetch feature in the Canary version today.