Microsoft will solve Windows on ARM’s biggest flaw beginning in November

At long last, Microsoft is ready to address the most significant shortcoming of Windows on ARM devices: the inability to run the common 64-bit code for X86 chips.

In a blog post on Wednesday, Microsoft said that 64-bit support was due in November, though only as part of its Insider beta program. When completed, it will allow Windows on ARM PCs to run every application that an X86 PC with an Intel or AMD chip inside it can run.

“We are excited about the momentum we are seeing from app partners embracing Windows 10 on ARM, taking advantage of the power and performance benefits of Qualcomm Snapdragon processors,” Panos Panay, Microsoft’s chief product officer, wrote in the post. “We heard your feedback and are making Microsoft Edge faster while using less battery, and announced that we will soon release a native Microsoft Teams client optimized for Windows 10 on ARM. We will also expand support for running x64 apps, with x64 emulation starting to roll out to the Windows Insider Program in November. “

By now, it’s a familiar story for anyone who’s followed Windows on ARM: ARM processors and devices like the Surface Pro X can run 32-bit and 64-bit ARM code natively. Most PCs, however, run 64-bit code written for X86 chips. Code that runs in 32-bit X86 mode must be interpreted by ARM processors, and will run, albeit with a performance penalty. Unfortunately, 64-bit code—again, commonly used by PCs—doesn’t currently run on ARM chips at all.

Microsoft, then, has operated on two fronts: optimizing code where it can to run natively on the ARM processors, as well as working on the compatibility angle to allow every app to run on top of ARM. But the lack of progress on 64-bit X86 compatibility has been one reason why laptops running on top of Qualcomm Snapdragon ARM chips like the Lenovo Flex 5G and Microsoft Surface Pro X haven’t received full marks. 

If you own a Windows on ARM machine like the Surface Pro X, make sure that you sign up for the Windows Insider program if you want to take advantage of the new features. To do so, you can go to the Windows Settings menu, then to Update & Security> Windows Insider Program and follow the prompts. As always, it’s a good idea to ensure every critical document is backed up—the Insider program is a beta program, and bugs and possibly crashes should be expected.

Reports had previously circulated that Microsoft was working to nail down the 64-bit X86 compatibility on top of ARM, which PCWorld itself had independently confirmed. Still, this is likely the most significant news for Windows on ARM of the past few years, and will allow Windows on ARM PCs to compete on an equal footing, from a compatibility perspective. 

As PCWorld’s senior editor, Mark focuses on Microsoft news and chip technology, among other beats.