Windows 10: Chrome and Edge slash RAM use thanks to this Microsoft backend change

Microsoft's Project Reunion effort unlocks a potentially huge memory-use reduction for Google Chrome and Edge.

Chromium-based Edge: Microsoft outlines new features

Google's Chrome browser has a reputation for being a memory hog. But thanks to changes in Windows 10 version 2004, the May 2020 Update, both Chrome and Microsoft's Chromium-based Edge browser will use a lot less memory. 

Microsoft has announced major memory-use reductions in its Chromium-based Edge browser on Windows 10 2004 that appear to come from its recently announced Project Reunion, a new API that attempts to unify Win32 and the Universal Windows Platform (UWP) apps. 

"Early internal testing results of devices on the May 2020 Update are showing a memory-use reduction of up to 27% when browsing with Microsoft Edge," said Kim Denny, a principal PM manager for Microsoft Edge, in a blogpost.

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Memory-use reduction depends on each device, its configuration and usage, but whatever the exact reduction, lower memory use should lead to a better experience for Edge users on Windows 10 2004, argues Denny.   

The new Microsoft Edge shares the same underlying technology as Google Chrome courtesy of Google's open-source Chromium project, which Microsoft now contributes to. Microsoft earlier this month began pushing the new Microsoft Edge to Windows 10 users via Windows Update.  

But the improvements to memory use coming to Edge and Chrome derive from Microsoft expanding the availability of Windows segment heap memory to Win32 applications

And that expanded availability, as spotted by Ghacks' Martin Brinkmann, is a result of Microsoft's Project Reunion effort, announced at Build 2020, which aims to close the gap between the classic Win32 app and modern Universal Windows Platform (UWP). 

Microsoft didn't have success in getting developers of Windows applications to adopt UWP. While legacy Edge was a UWP app, Google never made Chrome a UWP, sticking with Win32. 

As Microsoft clarified this week, Project Reunion rolls up the Win32 API with the UWP API and Brinkmann notes that the segment heap API was one of the APIs that was previously limited to UWP applications. Under Project Reunion, it's become available to all developers of Win32 apps. 

That should allow other Win32 .exe applications to reduce memory use too, including Mozilla Firefox and every developer that builds Win32 applications.  

SEE: Project Reunion: Microsoft's unified app strategy is still missing one piece

Google programmer and Chromium member, Bruce Dawson, clarified that memory-use reductions are likely to be greatest on Windows 10 PCs with CPUs featuring more cores, but they still could save hundreds of megabytes (MB) in the browser.

"Experiments with per-machine opting-in to the segment heap for chrome.exe suggests that this could save hundreds of MB in the browser and Network Service utility processes, among others, on some machines. Actual results will vary widely, with the greatest savings coming on many-core machines," wrote Dawson in a patch for Chromium.  

"Adding a SegmentHeap entry to the chrome.exe manifest will tell recent-enough versions of Windows (20-04 and beyond) to opt chrome.exe into using the segment heap instead of the legacy heap," Dawson explained.