Tip: Test Native Firefox for Windows 10 on ARM

Posted on January 5, 2019 by Paul Thurrott in Uncategorized with 28 Comments

If you’re one of the select few who is betting on Windows 10 on ARM already, you might want to begin testing the first native ARM third-party web browser early as well.

Embarrassingly, nightly builds of pre-release versions of Firefox for Windows 10 on ARM have been available since December 20, but I only found out about this today courtesy of Neowin.

“I’m excited to announce that we have bona fide ARM64 Windows nightlies available for download,” a post to a Mozilla public mailing list explains. “Please note that these builds are even nightlier than our normal nightlies on other platforms: they have not gone through our usual automated testing process, bugs are almost certain to crop up, etc.”

Based on my very early experience using the latest nightly build of Firefox for Windows 10 on ARM, the experience is a bit spotty. Initial app boot time is really slower—slower than that of the Intel versions of Chrome and Firefox, for sure—and, as Mozilla notes there are still missing low-level features like the Gecko profiler,  the Crash Reporter, the latest JavaScript JIT compiler, WebRTC, and more. Worse, a technology called Encrypted Media Extensions (EME) isn’t yet available, so popular media services like Netflix won’t work yet either.

But yes. These are nightly builds, so they will improve each day until this browser is deemed of high enough quality to ship publicly alongside the other versions of Firefox. And I’ve found normal web browsing to work pretty well, so it’s not a complete non-starter.

Feeling brave? You can download the nightly Firefox for Windows 10 on ARM installer here.

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Comments (28)

28 responses to “Tip: Test Native Firefox for Windows 10 on ARM”

  1. siv


    Is battery life the only thing that compells you to use an ARM based device, or are there other reasons that make you want to try it?

    • jchampeau

      In reply to Siv:

      I think what compels Paul to use ARM is so he can write about it.

    • Paul Thurrott

      In reply to Siv:

      This is a major platform effort that could point Windows in a new direction. Battery life is obviously part of the equation, but I don't feel that most Intel-type Windows laptops are particularly bad in this area. It's more of a total ecosystem thing, where ARM-based chipsets are physically smaller and require no active cooling and can thus lead to far more efficient mobile devices. Add that to the battery life, standby time, and seamless cellular connectivity, and you have the makings of the future of the PC.

      Of course, they need to figure out performance (which seems to be happening) and compatibility (which is trickier). This Firefox news speaks to the latter. And if they can pull off this in entirety, it's huge.

      • BigM72

        In reply to paul-thurrott:

        Given people are willing to buy Chromebooks that run web apps only. A Windows PC with familiar interface that has a proper desktop browser, Office for ARM, OOBE apps like Mail, Music, Photos, Calendar and some Store apps (especially basic games like Solitaire or Wordament) should be pretty appealing to consumers?

        Could this also be a motivation behind switching to Chromium - better performance on ARM than for Edge?

      • siv

        In reply to paul-thurrott:

        OK got it. I asked as I had the original ARM based Surface 2 and only recently retired it as it wasn't functioning too well. I subsequently had the Surface 3 and still use that as my only tablet for casual reading or watching movies.

        I did hope that like running Linux as I now do on my main PC having an ARM processor on my Windows devices might protect me better from malware, but not sure if this is the case or not?

        Since I switched to Linux on my PC I have a direct comparison between Windows 10 64bit and Linux Mint 19 and Linux is way more performant. I have a swap partition set up and I periodically check how much is being used and even when I have literally 30 applications and Windows 10 Pro running in a Virtual Machine it has never touched the swap file. Windows was into it all the time.

        I am interested in some of the comments you and Mary Jo have made about Windows Core as I would be really interested to see how much better a new Windows based on that would run.

        I feel that with the developments with ARM, the move to Open Source and their constant attempts with things like S Mode that MS are trying to get Windows to run with much less resources. Maybe they are planning an Apple style ditching of the Old Windows and moving to a New Windows that is much less bloated. If that is true maybe a switch to ARM processors is the way they are heading??

        • BigM72

          In reply to Siv:

          If you stick a general purpose Win32 emulation layer in to your ARM Windows, it's also going to run the malware in emulation and not provide you the protection. If you only allow ARM-native applications, you have some protection until malware writers starting compiling malware for ARM Windows.

          What you need is S-mode style banning of all executables not from the Store, then you get some more protection than standard.

  2. bill_russell

    I just wish companies could keep incrementally optimizing their OSs for their strengths and leave it there. Keep windows as windows for work, the iPad a simple consumption tablet and the chromebook just a web browser. Then move on to other products.

    How can companies that make more of a targeted usage scenario device that has a processor (i.e. iPad, chromebook) avoid always moving more and more toward making it a full general purpose computer. Even Apple who specifically addressed it and said they wouldn't do it, has been taking the iPad pro into being a full computer territory. MS did sort of the opposite of trying to make windows for touchscreen tablets.

    I also am not really impressed with google's efforts of play store on chromebooks, as it simply does not work well at least on the low end chromebooks which is what they were supposed to be about. Then they are talking about being able to formally install windows on them and they have Linux support with currently no GPU support. To be fair all of this stuff is optional ad-ons.

  3. bill_russell

    I've softened my frustrated stance on obvious half-hearted or doomed efforts (which seems to have been the case for MS other than Azure for the last decade at least) where they have huge coffers filled by main cash cows like Azure or, for Google, ad words. This keeps people employed on fun projects, which is what its all about. As opposed to being too-cautious perhaps like Apple. Personally, I just like to work on products and make a living. If it fails, well, then at least I don't have to support it.

  4. BigM72

    Why does Microsoft care about Windows on ARM? Because you can get Chromebooks on ARM. They want to try to match Chromebooks on spec bullet points.

    Worse still would be the risk that Chromebooks attain brand association as the laptop platform with best battery life.

  5. Tony Barrett

    I think everyone wants better battery life, but that will actually happen when the next battery tech appears to supersede Li-Ion. Windows on ARM won't help that much anyway - real world battery life of WoA is nowhere near what was promised. Also, who asked for an 'always on' Windows PC? Really? We all have our phones for that, which is where the majority of daily tasks is now done. It's almost like MS have done this whole ARM thing to try and stem the flow away from Windows. Compatibility/emulation? Another problem. ARM Driver support? Yet another problem. There are just too many issues for the average user who just wants a machine that will run everything they throw at it. Yes, x86 is a dinosaur, but it still does everything we need - for now.

    Unfortunately for MS, it's highly likely the next big OS advance won't be Windows at all. It will be a much smaller, lightweight OS that's scalable, secure by design, simple to support with a rich API, and I think this is where Google are trying to head with Fuchsia. I'm not saying it will do everything mind you, but the mentality seems right.

    • wright_is

      In reply to ghostrider:

      The battery life on my ThinkPad T480 is fine for the hour or so of battery use every month...

      I would say that 98% of my daily tasks are done on a PC, 1% on my Kindle (reading before bed) and 1% on my smartphone, possibly 2% if you want to include listening to Audible in the car.

  6. madthinus

    Following their progress, it seems that bringing it to Arm is alot more work than simply recompiling. They don’t have test hardware yet for the automated test bank and most of their automated test suite needs to be ported as well. This is a big engineering endeavor.

  7. skane2600

    I've always found the excitement over Windows on ARM a bit of a head-scratcher. Did it originate with the hope for a Surface Phone? (which wouldn't be viable ergonomically even if it ran full Windows). Was it was because current Windows users often found themselves far away from an AC outlet and so their laptops died? Was it because Intel was "The Man" and they wanted to stick to him? Whatever the reasons, do they still make sense?

    • glenn8878

      In reply to skane2600:

      Until Microsoft is fully committed, it will fail. Office needs to be ported immediately. They took forever to port Office to the Microsoft Store until no one cared anymore. It was too late. It’s likely, history will repeat.

    • wright_is

      In reply to skane2600:

      Windows has always been (or rather Windows NT has intermittently been) cross platform. When NT was first released, it was available for MIPS, DEC Alpha and a few other platforms. Itanium came and went as well. Then, more recently various ARM generations.

      But that was very specialist and always had a very restricted list of available applications, often Office or server tools.

      For Microsoft, it is good to keep the options open and provide alternatives.

      ARM looks promising, but although it can deliver the raw numbers, its real-world performance is still lacking. This is in part due to it having always been aimed at low power solutions. This is changing, but it will take time.

      • skane2600

        In reply to wright_is:

        I worked on a Windows project that used an Alpha processor and the compatibility wasn't 100%. One could argue that supporting multiple processors was a flawed idea, despite appealing to engineers' sense of a good flexible design, it didn't payoff. Sometimes the business case has to take precedence over the engineering case.

        But the ARM strategy is different, it's supposed to be used in the mainstream so a "restricted list of available applications" isn't going to be good enough. Likewise it must run the applications with good performance.

    • FalseAgent

      In reply to skane2600:

      how is it that after all these years people still have questions and this STILL needs discussion?

      we want thin and light low-end machines devices with decent performance and amazing battery life at reasonable prices. Intel has never delivered. Celeron, Pentium, and Atoms don't cut it. ARM has the potential to - given it can get native app support.

      • wright_is

        In reply to FalseAgent:

        I want raw power, virtualisation and fast SSDs and spinning rust.

        Battery life is pretty irrelevant to me, and probably 90% of my colleagues. Most have laptops for when they have to work at another site, where there is a docking station for hotdesking set up...

        Obviously there are a few mobile workers who do need the flexibility of long battery life and MS Office and email on the move, but the majority of workers are desk bound and if they even have a laptop, it will rarely be taken away from the desk, at most for an hour or so meeting - and half of them take the mains adapter with them to the meeting!

      • skane2600

        In reply to FalseAgent:

        The discussion continues because a good case still hasn't been made.

        Other than better battery life those other attributes you list seem equally achievable with Intel. Or are Intel chips so big and heavy that devices can't be thin and light? Of course for productivity use, a phone form-factor simply isn't going to cut it, so the thin and light aspects aren't going to be that important. As far as reasonable prices are concerned so far WoA devices have already failed and we know how poor the emulation performance is.

  8. ZeroPageX

    Excellent! This makes WoA more usable! I don't get why all Windows users aren't cheering this effort on. ARM increases battery life and brings more competition to the CPU market just for starters. What's the problem? I personally won't buy one as they currently doesn't meet my needs, but until they do, there are plenty of Intel offerings still out there.