Windows on ARM Getting Support for 64-Bit ARM Apps (Updated)

Posted on April 5, 2018 by Mehedi Hassan in Windows 10 with 27 Comments

HP Envy x2 (Qualcomm) Review Check-In: App Compatibility

Microsoft and its partners recently started shipping the first wave of Windows 10 devices powered by Qualcomm’s Snapdragon 835 processors. These devices, powered by Windows 10 S, are capable of running ARM and x86 UWP applications as well as x86, ARM, and ARM64 classic desktop applications, thanks to Microsoft’s Windows on Windows compatibility layer.

Redmond is now working on officially supporting 64-bit (ARM64) apps on its Windows on ARM platform. Windows General Manager Erin Chapple¬†reportedly told Engadget that the company is going to be releasing a new “SDK for ARM64 apps” that will allow developers to build 64-bit applications for Windows 10 devices powered by ARM processors, or recompile their existing apps for 64-bit. (This is not to be confused with 64-bit AMD64 support, which is not happening any time soon, if ever.)

The company plans to release the new SDK this May at its Build 2018 developer conference.

UPDATE: Here’s a Microsoft statement addressing the confusion around this topic.

“To clarify, Microsoft is planning to release a preview of the Windows 10 ARM64 SDK for Store and desktop apps, allowing developers to recompile their Win32 desktop apps to ARM64 so they can run natively without emulation,” the Microsoft representative told me. “With the SDK, x64 apps and x86 apps will also be able to recompile to ARM64 and run natively. We will be sharing more details on the ARM64 SDK Preview at Build.”

Also, Paul has written a follow-up for developers that better explains what’s happening.

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Comments (29)

29 responses to “Windows on ARM Getting Support for 64-Bit ARM Apps (Updated)”

  1. MikeCerm

    There's no such thing as "classic 64-bit desktop apps" on Windows. The vast majority of legacy Windows apps are 32-bit. Virtually all the 64-bit desktop apps that matter on Windows are apps that are currently maintained, available in both 32-bit and 64-bit flavors, and could probably be recompiled for ARM64 without too much effort. Certainly, if the developer cares about performance, delivering a native ARM64 build would be a lot better than relying on slow-as-molasses emulation.

    • jamJAR

      In reply to MikeCerm:

      SolidWorks current releases are 64 bit only.

      • MikeCerm

        In reply to jamJAR:

        "SolidWorks current releases are 64 bit only."

        Fair enough, but you probably couldn't run it even if WoA did support 64-bit emulation. The performance would be terrible, and most WoA devices only have 4GB of memory, which doesn't meet the minimum requirements.

    • Rafael Rivera

      In reply to MikeCerm:

      Classic apps refer to non-UWP apps here. There are certainly classic 64-bit desktop apps, e.g. Photoshop. ARM32 apps are not emulated and should be the focus for most devs. Hope that helps.

    • lvthunder

      In reply to MikeCerm:

      Who gets to decide what apps "matter". I use some apps that matter to me that are 64 bit only.

      • MikeCerm

        In reply to lvthunder:

        Name one -- I'm genuinely curious, because I can't think of a single 64-bit-only app for Windows that isn't a driver or something hardware specific.

        • skane2600

          In reply to MikeCerm:

          I'm not a gamer but here's a list of 64-bit only games (not all for Windows 10):

          • MikeCerm

            In reply to skane2600:

            "I'm not a gamer but here's a list of 64-bit only games (not all for Windows 10):"

            Presumably all of these games require more than 4GB of memory and/or desktop-class graphics to work, and if Chrome barely runs with 32-bit emulation, I can't image how slow games would run.

            "You might end up waiting forever."

            Yeah, maybe, but you can run the 32-bit version while you wait.

            • skane2600

              In reply to MikeCerm:

              The point is the inadequacy of Windows on ARM to run non-UWP legacy applications, if games require more resources than WoA emulation can provide, that's just further evidence of the inadequacy.

              "Yeah, maybe, but you can run the 32-bit version while you wait."

              It's not as if 64-bit is just a marketing term. If you need the additional capabiliites that a 64-bit version requires, 32-bit won't cut it.

              • MikeCerm

                In reply to skane2600:

                "The point is the inadequacy of Windows on ARM to run non-UWP legacy applications"

                WoA can run the vast majority of non-UWP legacy applications. It can't run current AAA games, or SQL Server, or CAD apps, or Adobe Premiere. You know what else can't run these things? Like, any thin-and-light laptop. The Snapdragon 835 has about as much power as an Apollo Lake Celeron, and it's meant for surfing the web and checking email. Complaining that it can't run Forza Horizon 3 is like complaining that you can't tow a boat with a roadster because there's nowhere to mount a hitch. But, even if you had a hitch, you still wouldn't want to tow a boat with a roadster.

                "It's not as if 64-bit is just a marketing term. If you need the additional capabiliites that a 64-bit version requires, 32-bit won't cut it."

                In practical terms, 64-bit means nothing but the ability to support more than 4GB of memory (which WoA already does), and there are some operations that can be done more efficiently than having to break them down into smaller 32-bit chunks. Who cares. Even if it did nominally support 64-bit apps through emulation, the Snapdragon 835 still wouldn't have enough power to do the kinds of things that you need a big desktop-class CPU (and GPU for). The performance penalty for emulating x86 is great enough that, for any of these high-performance tasks like gaming, video editing, or hosting enormous databases, you either need a CPU that can run the code natively, or you need the developers to deliver a version optimized for ARM64, which they'll soon be able to do.

                • Waethorn

                  In reply to MikeCerm:

                  I have an Apollo Lake Celeron and I can tell you that you're flat out wrong. Even from the videos of Paul and Leo showing the HP system launching UWP apps, those same apps run markedly better on a Celeron. And the Celeron runs everything, including x64 apps, and supports full Windows 10, so it also supports Hyper-V and such. And this shiny new UFS 2.1 support in the Snapdragon 835 (is HP even utilizing that?) is supposed to be faster than SATA 6Gbps, yet Windows loads up faster on a pretty stock Crucial MX500 SATA SSD on the Celeron.

                • skane2600

                  In reply to MikeCerm:

                  Actually, there's not enough real-world experience with WoA to determine whether the "vast majority" of non-UWP legacy applications can run under emulation.

                  MS hasn't made any statements I'm aware of that suggest that WoA is exclusively intended for "thin-and-light laptop"s. It seems you just want to exclude any examples people provide that disproves your position.

  2. Waethorn

    So now that the performance of x86 apps is out of the bag, is there anybody still out there that doesn't believe that their early demo on a Snapdragon 820 is anything but a fake?

  3. BoItmanLives

    Once again we watch MS just go through the motions of yet another bizarre and pointless product with no real use case or target market, that we know is going to be abandoned and internally probably already is. I bet WoA is barely a footnote at Build if it's even mentioned at all.

    Why? With Myerson out on his ass and the windows division gutted, the new rank and file doesn't remember or care why the predecessors even went down this WoA road.

  4. per.steinar

    Wunder what is happening with Photos hop Elements on ARM, since they demoed it running on Windows 10 for ARM.

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