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Microsoft Windows on ARM and SoC x86

By 5 January 2011 4 Comments

UPDATE – Looks like it’s no longer rumors, Microsoft will put Windows 8 on legacy-free x86 systems (I’m assuming something like Intel Moorestown) as well as ARM based systems.  I guess this is the shotgun strategy to cover every possibility in the hopes that one of them succeeds.  Sounds like a good strategy to have every basis covered, but I’m guessing that Windows developers will focus on the x86 versions because that’s what they’re familiar with and the software will work on existing systems.  All this assumes that Intel delivers on low power SoC platforms which they seem to be on track to do.

Ina Fried follows up on last month’s rumors about Microsoft Windows (not the smartphone version already running on ARM) running on the ARM CPU Architecture which powers nearly all the smartphones of the world with 5 billion devices projected to ship in 2011 by iSupply.  Two weeks ago, Peter Bright had given probably the best explanation of why such a move would be pointless.  The basic problem is that ARM based Windows will run 0% of all existing Windows based software.

Fried’s report is based on “a source familiar with Microsoft’s development plans” which doesn’t give us much to go on.  But for the sake of argument we’ll assume this source to be accurate and Microsoft is indeed planning an ARM based Windows.  Fried explains the reasoning behind this as superior battery life on ARM based systems, but that’s one of the smaller problems with Windows on mobile devices.  Microsoft’s main problem with Windows is its lack of a finger-driven user interface and its existing Tablet PC extensions are designed for mouse or stylus input.

The battery life difference between x86 Intel Architecture versus ARM architecture is rapidly shrinking and so is the performance difference.  The question is whether Intel will close the power consumption gap faster than ARM closes the performance gap, but Intel seems to be getting their sooner with their “Moorestown” product launched last year.  Moorestown type products hold a significant performance lead over ARM based products and its energy efficiency could probably achieve 8-10 hours of battery life on a 7-10 inch tablet form factor with 14 to 25 watt*hour batter.

So why doesn’t Microsoft use Moorestown?  Because Moorestown stripped out a lot of legacy hardware support that would prevent the stock version of Windows 7 from booting up.  But if Microsoft was interested in better battery life in ultra-mobile products, it would be far easier for them to create a version of Windows that runs on Moorestown and future legacy-free x86 products than to create and ARM based version.  The biggest difference is that most existing software written for Windows will run on Windows on Moorestown but zero percent of them will run on Windows on ARM without being rewritten or performance sapping emulators.

But the problem again is that existing Windows software is designed for keyboards and mice, not fingers so they’ll have to be rewritten anyways, at least the user interface portion.  But at least on Moorestown, they don’t have to start from scratch.

Update – Microsoft’s Jupiter 8 strategy might explain this dual ARM and SoC x86 strategy.  If this development platform truly allows developers to write an application that will run on both ARM and SoC based x86, then a dual CPU architecture strategy begins to make a lot more sense.


  • Nick R Brown said:

    Most interesting ARM – Microsoft product on the horizon that I have heard about this week is Microsoft utilizing System-On-A-Chip for their next OS for use on ARM, Intel, and AMD chips. The fact that this could save 3-6GBs on tablets and netbooks that generally have small SSDs or HDs is pretty significant.

  • larry seltzer said:

    I’ve been wondering WRT these stories if this next version of Windows relies on .NET a lot more than previous ones. It would be a good way to improve portability.

  • Michael Baumli said:

    This is a very exciting news from both the manufacturing side of things as well as the development angle.

    With a new platform to build or port Windows Applications, the open source community actually has another opportunity to develop applications and build up a resume for themselves. They can also fumble on this again and crash and burn like desktop Linux has year after year. Open source or not, this does mean lots of opportunities for jobs for developers. Microsoft has to get on the ball with two things. The first which George addressed is the UI, which I see happening with the rise of more touch screen monitors. The second is the development tools that will be launched with the OS. From listening to some Windows Phone 7 Developers, Microsoft has not been on the ball with this.

    From the manufacturing side of things, we could see larger and larger ARM processors that could come into competition with Intel while Intel tries to tread on the SoC market. This could be a lot of new devices with new uses and technology in places that we had not dreamed of yet.

    Hopefully with Windows 8, we will finally see Microsoft try to push out some unneeded legacy code which could help clean up a number of security flaws.

  • George Ou (author) said:


    Higher level languages always improve portability, but they’re never entirely portable. However, people want higher performance applications with smaller memory foot prints called “apps”. While .NET applications can be tuned to run well, it’s still nothing like a uTorrent client.